I had some of the same reservations/doubts. I felt like I had to leave to save my very sanity and so I did but it felt so wrong sometimes. In my case, that wrong feeling was my own sickness. My own co-dependency and confusion. The further along I got the more right I felt and eventually I *knew* I was finally doing the right thing. It has been over 4 years and I still know it was the right thing. It is often said here to just do the next right thing no matter how small the decision or step and eventually you'll end up in the right place. I did that and it worked.
I also discovered that the 'good dad' parts were made possible because I facilitated it all. Once I stopped doing that, so did all the good dad moments. My ex loves his children I guess and he has some good qualities (I did marry him after all) - and I don't care. He is horrible for me and he has moved away from his four boys so there are no good dad moments anymore because he isn't here. That has a tragic legacy I see every single day.
With independence and freedom I can see and accept all of who he is. The good, the potential (ha!), and the downright bad because I don't care how much you love your kids if you leave them behind that is bad. The mental gymnastics that were keeping me so confused and frustrated were inside me and clouded my thinking as much as the alcohol clouded his. Independence and freedom were a BIG part of my being able to think clearly.
Good luck with your house venture
I've bought two houses all on my own (once before I was married and once after I was divorced) and I have not regretted either purchase even once. Even the house we bought while married had the loan in my name only because I was more qualified alone than with him on the loan - I should have paid more attention to that sign, lol.