I've refinanced a house and sold it later on.
I've also sold a house and stayed in a relationship with my former co-owner.
Nothing you're talking about is carved in stone, hopeangel. Sadly, the only decision you're still faced with is whether you want to stay in this relationship. And you don't have to make that today.
It does sound like he's pressuring you, and that would fit with him being on his "better behavior" lately. That's how the rollercoaster goes.
i know i should probably set boundaries and conditions if we stay in the house and be prepared to follow through with them
And what would those be? If he drinks heavily again, verbally and physically abuses you again, blackmails you into sex again, pees the bed again, mistreats your animals again, you will.....what?
Might be good to go through that scenario in your mind first. And if you think you won't enforce those boundaries, don't make them. And if you can't live WITHOUT making them, consider not committing to anything new with him.
Good luck with everything.