Im (f 28), moving in with him (m 29) is almost giving me cold feet after a lot of drama over 6 years. What’s What’s the best way to handle it?

Therapy is expensive so maybe you guys can offer some advice. I (F-28) have been with the same guy(m-29) for six years. Although this past year has been very strained At the five year mark, I discovered he had been engaging in naughty activities for four of those years. When confronted, he factory reset the computer, said he "panicked" but that it also wasn't what I thought, despite having also discovered a video on his phone of him and a girl, who he pushed for me to be friends with before, in our bed…along with numerous nudes from girls on his facebook. He also went into my phone to delete a message i received from a gentleman i've never met before who said my bf had been fooling around and it was only right that i knew. My bf claimed to have panicked again when I confronted him and couldn't tell me why he'd "panic" if what the gentleman was saying wasnt true. I moved out not long after (november 2023). The only thing that really kept us talking is that he wouldn't give me back my cat. He threatened to off himself if I did and he knew that threat would get me because i dont play with suicide.. He would send me pics and videos of my furbaby. It took months to be civil with each other and eventually, somehow we just kinda clicked back together around june/july 2024. I do love him, I can't deny that. I know he loves me but he still decided to do those things for so long. And when we were apart, the idea of anyone else touching him or him touching them drove me insane. Even worse with the idea of someone else snuggling my cat. But I know if I had my cat, I honestly wouldnt have had reason to keep contact and this whole situation wouldnt be an issue right now. Anyway…After a few months, his landlord wants to sell the house that he's been renting and he doesn't want to buy it off the landlord. He started looking for other places to rent. My lease is almost up for the apartment as well and he was struggling to find anywhere to rent with having 3 cats and a dog. So he brought up buying a house and living together. We looked together and ill admit i got excited over one and thats the one he was willing to settle on. It will be all in his name btw, wed just split the monthly payments. I had my fears but thought maybe this would be a fresh start for us. He's closing on the house in a week and we've started packing both places. I'm starting to get so anxious in a lot of ways and really second guessing this decision. I still feel so hurt despite how much we've talked about things and I don't feel like this may end well but I'm struggling to swallow the anxiety and speak up. I don't even know what to say to him exactly even if I did try to speak up. Words have never been a strong point. And the idea of letting go of the apartment instead of renewing that lease scares me because thats like my safeline…Anyone else been in a similar situation? Am I just being anxious because I'm overthinking? Am I being a dumbass for allowing him back in? Should I have just kicked down the door and took my cat back, instead of being civil about things? I feel a bit lost on navigating my feeling and the situation. I unfortunately dont have anyone to talk with about this either. I'm not close with any family and don't have friends.