Oh yes OP I completely understand where you're coming from. I realised in my first year of marriage that I'd made a mistake but I stuck it out for another 16 years, because I'd made my bed etc. I did try to end it a few years ago but he did the thing he always did, "If I lose you and the DCs I'll kill myself" so I stuck it out for three more years. Until HE had an affair and decided life with the other woman was better.
I think I'll always be angry for my "lost" years, and I don't ever want to be in a long term relationship again, and most certainly never want to be married again, but I am so happy with my life. It's been nearly a year now and looking back on the me now to the me this time last year, I'm a completely different person. I don't know how my Ex wore me down the way he did; he was always the victim, I always had to support him but he never offered me support, he never wanted to hear about me it was all about him constantly, it still is. He chipped away at my confidence and self esteem and I never even saw it happening, he controlled me in ways I didn't realise I was being controlled, I just went along with things for an easy life because he would cry and mope and be sad if he didn't get his own way and then if he still didn't get his own way, he would lie, and sometimes steal and lie to get the new gadget he needed. Now when I look at him or speak to him it's as if something has been lifted from my perspective, I see him for the self-centred, self absorbed man he has always been. It pisses him off that he can't control me and I take great pleasure in doing little things so that he doesn't get one bit of control over me. He doesn't learn from his mistakes, he carries on trying to treat me like I'm nothing and I just play him at his own game. In the past 12 months he has not managed to score one point over me. After he left and he was happily ensconced with the OW he told me I would be a bitter and lonely single woman - I had to point out that I was never so bitter and lonely as when I was married to him, and single is brilliant. At least I can be by myself whereas he needs a woman to support him and I don't doubt for a minute that he's playing the same victim role with the OW.
When I was married I couldn't even look at myself in the mirror, I even brushed my teeth sitting on the side of the bath so I wouldn't have to look at myself. Now I see a happy, buoyant, well groomed woman staring back at me, with a little twinkle in my eye.
For me life on the other side is SO good. I'm happier, so the DCs are happy and while I worry about money and keeping things afloat and struggling with a social life because I have young DCs. I bounce out of bed every morning happy to face a new day, because it's a day when I'm not married to him.