I'm a chronic conflict-avoider, too, and was rather a doormat in my marriage (one that STBXH was all too happy to wipe his feet on). I, too, realised on some level that I was making a mistake before the wedding, but was too weak to break it off.
Fast forward ten years and my life was joyless and my self-esteem lower than when I got married.
When I told the DCs that we were separating, it was the hardest moment of my life. They cried, they wailed, it was dreadful.
Fast forward again to now, two years later. They are happy, growing in confidence, doing well in school, and I believe they are better off for having regular time away from their (narcissistic, manipulative but charming) father.
I have never looked back. I am so much more confident now. I can point out damaging behaviour in general terms without criticising him. I couldn't do that before. I can give them all the time and attention I want without being drained my his demands.
It is all so much better, for them and for me.
Oh, and I was richer on paper while I was with him, but felt so much better off when I left, because I could choose to spend or save without his judgement.