I repeated the cycle as well. More than once. I had to learn the hard way that he/they weren't the only problem - I was part of that same problem.
I had to buckle down and do the hard stuff. I diligently worked the 12 steps of Al Anon. That doesn't work for everyone, but it really worked for me. I also had to do some serious introspection to uncover some family history that led to some of my insecurities and I had to learn new ways of doing things. I interact differently today. I have new definitions of what "healthy" looks like.
I had to learn that what was comfortable and familiar might not be healthy for me at all. This was one of my most profound lessons. It made sense in my head long before it made its way to my heart. I can honestly say today that I'm not remotely attracted to people who in earlier times would have been a love interest, a husband, or a good friend.
I am healthier today, and I have healthier people in my life. For me, I had to do the work before I could get to a better place. It wasn't as easy as just walking away from my A. I wish I had understood that concept - it might have saved me some heartache.