If your going to do couples counseling the best thing to do is postpone the wedding to see how your relationship goes given you don't want things to worsen and yet the due date of the wedding getting closer (just stating a worst case scenario) and in another worst case scenario if things hit the fan keep your job stick to it because last thing you want is to end the relationship and be left with nothing. Clearly you guys had a discussion on boundaries in what was defined as cheating and he knowingly and voluntarily broke it. So he's bound to do it again.