I am sorry you are hurting Quin.
Know 1 thing ...this has nothing to do with you! HE is broken. If he does want to fix himself he will need to get into therapy to find out why he is doing what he is doing. I am sure he has issues probably going back to childhood.
It is up to you to stay in a relationship with him or not...
It is hard to reconcile, they say it takes 2-5 years to recover...and that is with a completely remorseful partner.
I don't know how old you are or if you have kids, but think long and hard before you marry this person. You may spend your life wondering what will come next....or maybe he will get his shit together and fix himself, but you won't know that, really know that, for a while.
right now ...
It's hard to accept rejection and I'm having a hard time believing that this is actually who he is.
^^^ he is showing you this is who he is...don't accept that in your life, demand better.
I would get into some therapy and start healing myself..get strong enough that you will be fine if he goes or stays...You need to be ok with you.
You can do this, it sucks...but one day at a time.