...and then I remembered about the OW (bad). Am I the reason he was distant? Did I break him or was he like this when we met? Will he be better with someone else? Is this all my fault?
Kas, I am a distancer by nature. When I am threatened or scared or hurt, I shut down. This includes shutting down conversations where I am uncomfortable or have something to hide. I avoid or when pushed give a close ended answer is shut the conversation down. I do it today when he asks me things - like asking me about the house. I do it when I don't have an answer or when I know it could lead to a conversation I don't want to have. Distancing is about protection. I do it to protect myself, my ego or the narrative I've spun in my head. It is not your fault. He did not engage because it may lead to a conversation or an outcome he didn't want or wasn't yet ready to face.
Will he be better with someone else. Who knows. If he has done the work and comes out of the other side more evolved, then maybe. That is outside your control. All you can do is work on you. If you do that, then you will definitely come out better the other side. And then it won't be a case of whether you are better of with someone else, it will be a case of you are just better off.
Is some of this your fault? Probably. No single person is 100% responsible for the breakdown of an R. We all contribute (to varying degrees). But he quit the R. That's on him. He has to live with it.
But you need to get to a point where you recognise and own your contributions. This isn't me having a go at you. Sometimes we have to look inside and see ourselves, warts and all so that we can work on becoming a better person I am a distancer - I am trying not to be, not just with him (tbh - I am still a distancer here), but with every other uncomfortable interaction I have. I make an effort to listen to hear people's stories and interact positively with them. I try and be more appreciative of what I have and the people that are in my life (and yes, even my H). There are a hundred and one areas where I fell short in our marriage - I am working on changing those. If I ever get an opportunity to have another meaningful R (with my H or with someone else) then I know I will be a better partner. History will not repeat.