a) I would be absolutely devastated that he didn't respect me enough to be faithful.
b) I'd be devastated he didn't respect/trust me enough to be honest about his feelings towards men (even if he "didn't want to hurt me"
c) I would be devastated that he disrespected me by cheating on me.
d) I'd be thankful that it was something he could finally face, and perhaps would be the beginning of a wonderful very very close friendship for us as co-parents.
after I got over the anger and disrespect of being cheated on. And I would not stay in the marriage.
However, is it something he is really into, or something he was just curious about?