I am so grateful for all the advice. Obviously this is a big dirty secret so I can't talk to anyone about it which makes it so much worse (Well I've told one friend but I know shes disgusted which is fair enough).
Initially it was just physical attraction but then I did enjoy the contact and flirting and attention and yes it does mean something is missing in my own life. I hate to admit it but you guys have made me realise this. I've had bf's for years and I do miss the attention (I'm not insecure, just used to male company). But over time I did get to know this guy well and we do have lots in common (not justifying, just explaining) and yes he was expressing strong feelings for me and saying he'd love to see me outside of work but couldn't. i have wanted to spend time with him but I've never wanted a full blown relationship with him. I've known from day one that I didn't want him to leave his wife for me. That never entered my head. I'm a go-with-the-flow kinda person and thats blown up in my face now. I do feel sorry for his wife. I don't want to be the cause of her heartbreak. I'd never get over being the cause of that. I'd hate to be married to him, hes clearly very weak for doing this and I am wary of him in work. I have tried to observe his interactions with other women (I hate that I even do that) just to see if hes overly friendly with anyone else. I don't think he is.
Theres no way anyone suspects in work cos we barely say hello to each other and we meet in an office to talk to each other maybe once a week. I've just gotten myself into a bad habit here and I am totally waiting for him to contact me each day now and its such a pain. I keep checking my phone hoping to see his name and I'm sick of it. I'm a bit stupidly obsessed now.
As far as him being a serial cheater, I don't think he is. I think hes been quite bad at this affair. If he was good he would have slept with me right? He could have had me many many times by now but hasn't. And I don't know if this is text book cos I've never done this before so I've no idea what men do in this situation. And I do have feelings for him so maybe this is making me blind to this 'text book' behaviour (is it text book???).
He does have a year old baby which I know makes this doubly bad (pls don't kill me) and he goes around showing off pix of the baby to people in work and I do think.....oh my god if they all only knew. He plays the happy family man well and then texts me saying he'd love to get stuck into me. I'm painting a very ugly picture here but I need to talk about this so badly as its getting to me so much at this stage.
I have thought that he was very bored and this has been exciting to him and some fun but i think he may back off now due to the feelings that we've expressed and its all too serious now. I don't contact him so hopefully it'll die off and he won't contact me cos I find it impossible to ignore him.
I love my job and plan to stay in the company for years so I need to get my act together for that reason alone. I need this job badly and if anything got out, that'd be that. They'd all blame me cos hes like a nice little family man and I'd be the most hated b1tch in there. nightmare.
Thanks again for the advice. Its fantastic to get opinions