I am bipolar and almost cheated on my husband a couple times during a recent episode. He doesn't know how close I got to doing it. Trouble with mania is these ideas we get feel so right at the time and we are sure we must do whatever it is we are compelled to do. And the hypersexuality is a killer. I spent a week thinking about nothing else.
A second chance seems to me to be an OK move in this situation, but you do have to get yourself therapy so you can move forward, if that's what you want.
I sympathize with you both.