KC, you've gotten so much good advice from so many people, and I do truly feel for you. It's hard to see someone continually remain in or insert them selves further into a situation that causes them pain.
Obv I am not a lawyer, and it varies state by state, but my XH did try to sue me for money that I had before we were married. I was able to prove it was mine, and won. He sued me after the D was final. But, I also had an attorney. My XH was super abusive, and I blocked him in every avenue possible, and my attorney handled the rest. It was great. I was in a painful situation and too scared of the unknown to get out of it for a long time, and it was the best decision I have ever made. I grew and learned a lot. The other side of D can feel really good. I never thought I would get married again, but I am, and despite going through some tough times together, am still in a good place with him. Doing DB has been helpful for me personally WAY more than helpful for our marriage - helping the R isn't the actual point of it, which I know others have said more eloquently than I can currently. I don't think anyone here has been the perfect DBer - it isn't supremely linear in nature. My H returned because he saw I put in the work for myself, and not for him or to get him back.
I am going to also echo that you could really benefit from IC. It's interesting to see that you always blame his love for OW/his feelings for her as the reason that he is not coming back, even after saying you've identified your parts in the breakdown of the M. He isn't doing xyz because he is out with her, etc. Honestly, it really doesn't matter what he is or isn't doing. I am not saying this in a hurtful way, but there's a strong possibility that he is gone because of stuff that only has to do with you and him, not him and someone else. That can be really hard to admit to yourself, and IC can be really invaluable with that, too. I think it'd help you in the acceptance part of this to stop making it about OW and his feelings for her, too. It didn't seem to be a large part of the dynamic of why he left, and doesn't seem to come into play when you interact.
I also agree with Beth about overanalyzing everything. Take time for your actual self, not the you in M, and stop worrying about H. I know this is way easier said than done, all of it is, but you can't practice that if you're so busy overanalyzing and all of that.
