Morning is a good time to have a wander round the stalls tent, bracing yourself for its chaos, the good-natured throng shuffling haphazardly round the stalls in search of bargains: this year's must-have fashion accessories - silly hats anyone?; gifts and toys which you will play with during the weekend and not look at again; musical instruments you've never heard of let alone know how to play; lamps, rugs, jewellery and all sorts of paraphernalia which you wouldn't give another glance to in different circumstances, but which in the louche surroundings of Cambridge become irrestistible. Jamie and I did the rounds, buying bags and earrings, a musical egg and a penny whistle. My major triumph was to get him to buy a beautiful, deep green sarong. I never thought he would do it, but the combination of a couple of early morning lagers, my feminine wiles and the relaxed Cambridge atmosphere talked him into it. He looked so dashing, so gallant, striding about with legs bare, a tantalising glimpse of thigh showing from time to time. I was so proud of him that day, so much in love with my darling young man. Oh, so much, so much.

There are so many things to divert you at Cambridge and so little time in which to do it. When you arrive on the Thursday the weekend seems to stretch before you endlessly, but Sunday snaps at your heels, snarling its warnings of "Monday" and "back to work" before you realise what is happening. No Cambridge is complete without a trip to the Guinness tent, a shambling celebration of drunken revelry, a teeming mass of staggering, slurring drunkards shouting and roaring above the sound of the free-for-all Irish music session which sets up at the back of the tent on the Thursday and never lets up until the last pint is poured on the Sunday.

Jamie and I had a couple of drinks there and headed out past the main beer tent, another heaving ghetto of drink-maddened bodies, towards the Club Tent. The Club tent offers a mixture of amateur musicians and up-and-coming professional acts, and is a congenial place in which to spend an afternoon. The quality is mixed, but it scarcely matters: it is the ambience that counts at Cambridge, the mix, an occasion when inhibitions are conquered. Jamie was the most relaxed I had ever seen him, mellow and happy, comfortable in himself and his surroundings. Bit by bit, piece by piece, he let himself go, my uptight, wonderful young man, and gave himself over to the moment. He never looked happier, and nor, I think, was I.

We wound our way round the knot of food stalls covering the gamut of culinary styles: Mexican and French, Carribean and Indian, plain old English or exotic Thai, everything was there; hot curry and cooling fruits, wonderful red meats and vegan pitta breads, meals or snacks. The smells poured around you, a wonderful, ever changing mélange of aromas wafting in the air, floating about you, covering you, attacking your taste buds, compelling you to buy them, try them, fill yourself and sate yourself, join in and enter the carnival. It was impossible to resist.

Saturday evening was warm and fresh, the high-point of the weekend. We'd seen some fantastic music over the last couple of days, from the likes of Old Blind Dogs, Eric Bibb and the magnificent Kate Rusby, who sang my favourite song of all time, "Our Town". She has the most beautiful voice, natural and unforced, breathy and melodic. Her haunting cadences, wonderful pitch and earthy, almost melancholic delivery make it a beautiful, evocative work. The song itself is a woman's plaintive farewell to her home town after forty years. It is a song of loss and love which particularly appealed to Jamie and me for some reason: tempting fate, I think, we declared it our song.

"And you know the sun's setting fast
And just like they say nothing good ever lasts
Go on now and kiss it goodbye
But hold on to your lover 'cause your heart's gonna die"

With the arrogance of youth, the sureness of love we embraced the pathos of the song, without acknowledging that such a thing could ever befall us. We sang of our hearts dying because we knew they never would; our certainty, our togetherness, our mutual love would see to that.

As the official Saturday night entertainment on Main Stage One wound to a halt Jamie and I wandered hand in hand down the side of the field, towards the food stalls. There was no point in heading for the tent straight away because everyone makes for the narrow exits at once and huge, good-tempered crowds build up, which take at least half an hour to clear. We took a leisurely stroll beneath a clear, crisp sky, heads buzzing with the music. Jamie looked so handsome in the moonlight, a blue shadow falling over half his face, while the other half basked in a golden glow. He looked so happy, so relaxed, the furrows that normally scar his brow lifted and his eyes bright and keen. I knew at that point that I loved him as I had loved no other man; that I wanted to be with him, to be part of his life, to share his experiences, his ups and downs, triumphs and failures. My beautiful, shy young man had quietly sneaked in and stolen my heart. Unassuming to the end he stared at me, blissfully unaware of the tumult going on in my head. He gently hooked his hand behind me and pulled me towards him, placing the most delicate kiss on my mouth. It was all I could do not to cry. My man, my wonderful young man. I took his hand, squeezing him tight, and we carried on, lovers alone in a field of 10,000 people, oblivious to everything but themselves and their moment.

The highlight of Cambridge Saturday night is always the same, and has nothing to do with what happens in the main tents. It is the after-festival session at Johnny Crescendo's tent, which has been happening ever since I can remember, an annual fixture to which afficionados look forward more and more with every passing year. Johnny is an ordinary festival-goer who camps out in the small wooded area to the west of Cherry Hinton Hall. A series of tents are strung out among the trees and above them hangs a giant canopy. Each festival Saturday this is the scene of an immense session which goes on until the early hours. Anyone who wants to sing or play is allowed their three minutes of fame in front of a large, appreciative and very mellow crowd.

By the time we had finished our stroll round the perimeter of the Festival site the session was getting into full swing. A rather self-conscious youth, not unlike Jamie, as it happens, was singing what sounded like his own composition, and as the song progressed was visibly gaining in confidence; by the end he was letting rip with gusto and built to a heady climax, pride and satisfaction at his achievement emanating from every pore. I clapped loudly, my arm wrapped around Jamie's.

A few other acts, solos and groups did their pieces under the guidance of our host, Johnny Crescendo. He was brilliant at marshalling the event, keeping things flowing, making sure everyone who wanted to was involved, keeping the atmosphere light and relaxed. Perched in his wheelchair, which gave him a sense of authority over the rest of us flopped on the canvas flooring, he would point at people asking if they wanted to participate; no stigma was attached to anyone who didn't, no-one was made to feel uncomfortable, but still the music flowed, the evening progressed, a musical and fraternal delight.

For hours it went on, the crowds milling to and fro, sometimes huge, a crush, standing room only and then, unaccountably, a quieter period, a lull in proceedings before, equally unaccountably, numbers would suddenly rise again. Jamie and I sat throughout, arm in arm, head to head, two as one, swigging from our brace of four-pint jugs judiciously bought in the beer tent just before last orders. Johnny Crescendo was still seeking out volunteer performers, politely hectoring and cajoling people who obviously wanted to perform but hadn't plucked up the courage.

And then he turned to me.

"And what about you?" he asked.

I was about to say no, I couldn't possibly, but Jamie gave me a quiet squeeze on my arm. He didn't say a word, but I looked into his eyes, looked at my lover who had travelled so far in this brief weekend. How could I refuse? How could I act sensibly when he had divested himself of so many inhibitions, had opened his heart to me, allowed me a privileged glimpse of the man within? How could I? I couldn't.

"Okay," I said. "Can I borrow a guitar?" Instruments, particularly guitars were fairly common currency within Johnny Crescendo's: we shared, a commune of spirits. A neat steel-strung guitar was passed over and as I sat cross-legged I settled myself, pretending to tune up in order to hide my nerves. I looked at Jamie and raised my eyebrows, inviting his support. I had never performed in front of an audience before, not even, I realised, Jamie himself.

"This is a song you may have heard earlier today, sung by a much better singer than me," I began. "It's called Our Town."

Everything had gone icy cold, and what light there was seemed to have disappeared. I felt as though I were in limbo, cast adrift in a dark desert. Gripped by nerves, I began to play the opening bars, my fingers like lumps of lead galumphing around the neck of the guitar. And then I started to sing.

At that moment the nerves departed. "Up the street beside the red neon light," I began, "that's where I met my baby on a hot summer night." I looked at Jamie, who was smiling back at me with undisguised pride. "Go on now and say goodbye to our town, to our town, can't you see the sun's setting down on our town, on our town, goodnight" I sang, the thrill of the moment, the magic of our love filling me. I soared through the song, effortlessly, flawlessly, better than I had ever sung it before. "Goodnight," I finished, "goodnight."

I often wonder if anyone who was there that night remembers my song? Could they ever realise what drama was unfolding before them, could they ever know that two people's lives were being irrevocably altered in front of their eyes, in the course of those four minutes, that simple song? Did they see the flash of love between us, did they notice the transformation from desire to need? Did they know that we began that song as lovers and ended it as Lovers? Did they?

I think not. And that is the magic of the moment. For Jamie and me it was the most significant event in our lives, for everyone else a pretty song sung (I hope) well. For us it was the start of a new adventure, for the rest an amusing diversion in a weekend of amusement. And so it should be, because love is a personal thing, an intimate moment, an unfathomable emotion. No-one can ever understand someone else's love. No-one knew that as I finished, picking the final few notes, I had tears in my eyes, tears of joy, tears of shared love with my wonderful Jamie. I was singing our song, I was singing for us. Together we had shed our skins, had recreated ourselves as a pair, had unequivocably matched ourselves. I looked at him, his big proud eyes, and listened to the applause as I finished. But I could see only him, hear only him.

"Will you marry me?" he said.