"Constant affairs" means he has established himself as dishonest with repeatedly cheating and lying. If you are ever going to have a really good marriage, he has to repair his character for the long run.
This repair has to be because HE wants to be a better man, not because he wants to please you. Changing character is difficult work because there are so many temptations and other reasons.
You say you are working on your marriage. I hope that means you are attending marriage counseling with a marriage-friendly therapist who is ALSO skilled at character repair. From your description, I don’t think he has the maturity to authentically develop his character. Also, he is talented at making everything your fault, probably to justify his misbehaviors.
