From what you said " I don't feel anything for anything" -- to me it sounds like you are clinically depressed.
You should see your medical Dr to discuss.
As for the both of you cheating, you BOTH need to figure out WHY you did this. You should both be going to individual counseling. NEITHER of you are good marriage partners to the other due to these issues. You need those worked on and fixed before you can be good partners.
For YOU I would first work on finding out if you have depression and get that under control.
If you don't feel anything for anything, you won't feel anything for him or your marriage.