First of all, his condition doesn't "make" him do anything. There is some need that is not being fulfilled in his life and it may not even be anything you can prevent. Many men just cheat and they are fine with it. As for me, and I'm only speaking for me, I felt wanted and needed a connection like that. The first time I felt that I was fulfilling a need to save my marriage. The second time I just got caught up in "love" and wanted to be with someone that i thought was my true soul mate. My wife had distanced herself from me and I felt hurt and betrayed. I turned to self-destructive behavior, as many bipolar people do. I didn't care about consequences and that's what is hard for people to accept. You know things can go bad but you either don't believe it or just plain don't care when you're "up"... but you will when you're down or leveled out. But, I must agree, that at that moment you make a decision based on a distorted reality. And the scary part is that you think that you have the most clear mind you've ever had. In reality it's the exact opposite. What is scary is how long an episode can last with someone who is not of the bipolar I variety. It's scary to know that even you can't trust your own feelings. The love, the feeling that this hole in your life has been filled by someone else, is false. As for the urges, they are unresistable at times. You feel this need to do something, anything, to change your situation. For some it's shopping and others it's sex. Most people, including the person going through it, don't realize what is happening because bipolar II people can carry on productive lives without being completely crazy. their behavior may seem questionable or unreasonable but not crazy. But their reasons for doing it or their feelings are unjustified but they don't see it... they believe they are right. So, I would say that being detached can be normal. After all, it's never as earth shattering to the cheater as it is to the one who never saw it coming. But he should be able to empathize and realize he hurt you. He may not care, and that is a whole other issue all together, but he should make lifestyle changes to keep you. If not, it's over. He will need time. I felt bad right away but it took weeks for me to realize 1) just how much she truly loved me - I had convinced myself she didn't, 2) that my wife actually was serious about staying together and 3) that I wanted to be with her. Then there's the problem of actually doing it and that will take months to be able to really trust one another. He'll see other women, he'll want them, but he needs to decide in his own mind, no matter how he feels, that he can't. He needs to burn it in and remember it always. It's easier said than done but he knows right from wrong when he's manic.