I found out that he emotionally cheated on his ex Wife, how long he was married and when he divorced, he lied openly to me about the number of people he’s slept with, he’s lied to me saying this one girl was his brothers gf (which was a lie because he was hooking up with her), you get the jist ... just ALOT of unnecessary lying.

OP....you are 23, there's a large age gap, and you just learnt about a whole list of lies. Why do you still call him your fiancé?

What do I do? Do I put us into couples counseling?

Why waste money? This isn't a couple's issue, this is a personal issue. Your SO has clearly issues, and zero respect for you. A woman his age wouldn't have put up with this bs, hence, why he probably seeked out someone younger.

Just walk away from this mess now.