Sorry about your family situation. Be super careful with evidence of USC cheating. You divorcing shortly after getting conditions removed plus evidence of cheating going all this time since beginning may suggest to USCIS it was a conveniece marriage for immigration benefit or somebody was paid. I'd try to keep things cool between you and your soon to be ex and divorce without too much drama. Forget about N-400 under 3 year rule.
Good luck!
P.S. on the day of approval, did you still live together or one of you moved out? I can't blame if one of you moved, given the dangerous situation. But if moved, was USCIS notified of address change?