Actually, and I don't admit this often, *I* cheated on my ex (before we were married). It was a torrid love affair and I would regret it... if my ex and I were still together (but he dumped me, so I don't regret it now in the least). I disagree that if you cheat once, then you're guaranteed to cheat again. I will NEVER do that again because a) I love my husband more than anything in the world, and b) I would never want to relive the guilt and the internal conflict.

There are always "extenuating" circumstances that "justify" cheating. But it's cheating nonetheless.

I guess I don't have any real advice for you other than hoping you'll do the intellectually smart thing and get out. Don't have the guilt hanging over your head of wrecking a marriage -- it would be thousand times more painful to the wife to be left for another woman than to have the marriage just drift apart. And as things stand, he's not doing you justice -- he's keeping you unavailable to find legitimate love with someone who can commit to you. You're not being fair to yourself by staying in this situation.