I think you didn't get all your ducks in a row before you pulled the trigger. You should have looked through his phone to confirm. Any asshole can use a picture of your partner, create a tinder account to catfish someone or to hurt him or you. I think dumping him was the right move for the gaslighting but the jury is out on the cheating.

Just block him. You mistake was trying to stay friends with your ex.

Break up. You don't share the same life goals. Don't waste your time hoping he will change his mind