I am with sarahsweet here. Perhaps maybe unmedicated bipolar disorder caused her to be unstable and maybe you think she made impulsive decisions during her manic episode. Maybe.

But affair lasted 6 months. Not one night stand. And only ended because she got caught, not because she was remorseful or something.. I don’t know how bipolar disorder could explain or cause that.

6 months affair takes a lot of consistent effort not only effort to maintain but also effort to hide it from one’s partner. Does bipolar disorder causes that? I doubt it.

It’s your choice to stay with unfaithful partner but I am not sure why it’s matter that she has bipolar disorder