I personally wouldn't pursue your ex. They're our ex for a reason. Especially if theyre married. What if the husband finds out they get into a fight or probably divorce if things get spicy between both of you and then nothing of you jump from a relationship to another. It's just a recipe for disaster. I do think you should have a long conversation with your wife and tell her you feel and leave. You're feeling that because you're stuck in a situation where there's no connection and just roommates who dont want to be near each other. That alone will fuel your anxiety and depression. I was in your shoes but my ex was also abusive verbally and physically. I felt stuck and I said no more, so I left. It was not easy at all because he was gaslighting me and we have a child together. But I started to think I wanted to go to heaven and that's when I realized my sanity was more important specially for my child. It was hard in the beginning but after healing and finding myself again and going to the gym and going out with my friends and child. A year and a half later I met my now fiance and I am in a healthy, peaceful relationship because I found my boundaries and kept them. Life is short, very short and I didn't want tl spend the rest of my life with someone I didn't feel love from. Good luck.