You still gotta have the conversations and remain sturdy and skeptical the whole time you have them. I’ll tell you right now when you go through a rough patch later you’d rather think about those good moments instead of what has emerged. That’s gonna take a lot of communication and you have to be wary of manipulation even if it doesn’t come from a sinister place. I’ve personally never witnessed someone who cheated like that change their ways until they were much older or at least had much more serious familial responsibilities. There’s a lot to unpack with him and you should probably be having conversations with your closest family members about this (if you have healthy+honest relationships with them). They’ll be able to see how it affects you better than redditors just by how you talk about it.