I've been thinking about starting a thread like this too...
I have been involved in an affair (mostly emotional, not much physical contact really) since September and it has been the most horrendous, difficult and depressing 5 months of my life. Over the last few days I've turned a bit of a corner - yesterday we didnt text at all which is a first for us since this whole mess started. I'm just concerned now about keeping it up, we work together in a fairly small company and I'm worried that unless one of us leaves, it will never properly be over. The problem with that being that we both have our dream jobs that have better pay and conditions than we could get anywhere else. I suppose you reap what you sow...
Anyway, what has helped me reach this point has been:
Identifying what led to this behaviour in my marriage - I have had a few frank conversations with my DH about what our marriage lacks and how I feel. He has been brilliant and has taken on board much of what we've discussed
Attending individual and couple counselling re the above
Turning all of my thoughts and attention to DH - we've been ignoring each other for a long time, and I needed to refocus all of my attention from the other man onto my DH
Realising my behaviour just lacked respect for everyone involved. It lacks respect for my DH and the OM's wife (and children!). It also lacks respect for myself - I would never stoop so low as to see a married man if I was single, why the hell would I do that when I'm in a relationship?!
Thinking about how cliched, nasty and selfish my behaviour is. Yes, I think there are some serious and deep-rooted reasons for it, yes my marriage has slowly been decaying, but although these are reasons they do not excuse the behaviour - nothing can.
Remembering how bloody unhappy the whole situation has made me! The stress, secrets, lies, heartbreak, jealousy, sadness, shame, guilt... Not worth it!
Anyway, sorry if I've high jacked your thread a bit- just want you to know there are others going through similar. Breaking off contact is the best thing you can do - then think about how and why this has happened, and what your future looks like. Good luck!