i slept with my flat mate

... but he was also my landlord. Jilted lodger Jo Barton on the perils of mixing sex and socks - or the fork-off syndrome

y surreptitious and doomed fling began a couple of months after I moved into my first London flat. Work was pretty tough at the time, I'd just split up with my boyfriend, I was broke and, constantly exhausted. I regressed to the sad state where a Friday night spent with a bottle of wine and a takeaway, watching Father Ted and The High Life, was the climax of my social calendar.

One of my two new flatmates, Jon, was also becoming a social recluse, primarily to save money for a trip round the world. He was also a 6 ft snowboarding dude with long blond hair to die for, so it was no real hardship sharing the sofa and a piece of pizza with him. Then late one Friday night, when our other flatmate Lisa was staying at her boyfriend's house, I was stomping around the living-room moaning to Jon about work and being manless and having no wine left. He gave me a friendly hug to cheer me up, and then we were kissing, and then we went to bed. Simple. We were mates, now we were great lovers. Just one small problem: ''Let's keep this quiet - it's not fair on Lisa for us to be shagging around the flat,'' was his delicate suggestion. In all the initial excitement, it seemed a reasonable comment, and at first our affair was fun. The subterfuge added an extra frisson: crafty snogs in the kitchen when it was our turn to do the washing up after a dinner party; sneaking out of each other's bedrooms before Lisa went for a shower in the morning. It was just like being 14 again and seeing my first unsuitable boyfriend behind my parents' backs. After a few furtive weeks, during which I'd hardly seen any of my friends because I was so eager to be waiting in the flat for Jon to get in from work, I began to hint that we should ''come out'', but he wasn't too keen, saying it would upset the equilibrium of the flat. Warning bells should have rung, but by this time I was too besotted to notice. Three days before Christmas, he left to visit his parents in Scotland. We said our shady goodbyes, and I hugged our secret romance all through the Christmas break.

When I returned to London in the New Year a few days after him, he picked me up at the station and we went straight back to my room. The sound of the front door slamming shut awoke me the next morning in an empty bed. I got up and staggered into the kitchen, where Lisa was making breakfast. ''Jon went out early this morning,'' she remarked. ''He must be really keen on this new girlfriend. He met her up in Scotland over Christmas; she works in advertising, earns a packet. He's seen her nearly every night this week."

I stopped breathing. She picked up her cereal bowl and strolled back into her bedroom, oblivious to the effect of her words. Late that night, long after I'd actually given up trying to get to sleep by counting sheep trampling over his balls, he came home - mercifully alone - and crept into my room. I told him that I knew. At least he had the decency to try to look sorry. Yes, he had been going to tell me (oh, really); he was a bastard (10 out of 10 for observation); and did I want to be adult about it and go out for a drink with him and his new, rich, girlfriend the following evening (what can you say?).

I stuck it out for a month, having a wildly, childishly, bitter time slamming doors, ignoring him on the stairs and doing all the washing up except his (even if it meant leaving just one bit of dirty cutlery - what we jilted flatmates call the fork-off syndrome). If there was any justice, he would have been the one to capitulate and move out first but, unfortunately for me, it was his flat. The worst part was that I couldn't even talk about it. I felt far too stupid to explain to Lisa or my friends the real reason for suddenly leaving that lovely flat and moving halfway across town (where I wouldn't run the risk of bumping into the happy couple mark 2). Landlords and love affairs simply don't mix, unless you are the one with the deeds to the mortgage. The next time I slept with a man I shared a house with, I made very sure we were engaged first.