When he finally came home, we talked. We talked for hours, deciding whether we could work things through, if there's enough to build on to save this marriage, and despite my hurt, I asked to try again. We both agreed there's enough love to start afresh.

Last night, he came home from work and, as we watched television, I did something I haven't done in years - I performed oral sex on him. It's not something I have particularly liked doing in the past, but last night was different; I enjoyed it.

Afterwards, he went quiet and wouldn't meet my eye. He shrank away from my touch and stared with intent at the television screen. Then he admitted it and my world fell apart; he has feelings for someone else. She's someone he knows through work, and although apparently nothing has happened, he felt like he was cheating on her whilst having sexual contact with me. I felt so deeply humiliated.

He told me that he finds excuses to phone her just to hear her voice. That she brightens his day. That although they just flirt, he feels like he's cheating on her in our marriage.

I started to break down, but controlled myself. I was determined not to let him see me cry. He kept apologising, telling me how sorry he was, asking whether I knew what he was experiencing. No, I replied. I have respect for my marriage.

I shut down. I wasn't prepared to make everything Ok for him. He kept pulling at me, asking to be held, and I sat, numb.

He started crying, and told me it was a lie, that she didn't exist, that he'd said it because he suspected I was having an affair and thought it would make me confess. He said that he thought I was giving him oral sex out of guilt.

I don't know what to think any more. He looked so genuine when he was telling me about this woman, and it was such an elaborate lie to make. It's not the first time he's claimed to have been infatuated with 'a woman through work,' although he's only ever said it during arguments and has always apologised afterwards, claiming to have said it for reaction.

I wonder whether he was telling me the truth, but backtracked when he realised that our marriage would finish through his revelation.