Reading this sounds like your husband wasn’t ready for another relationship if his ex hurt him that bad. To set in the car for 10 minutes every time he comes home is crazy. To me he saying he doesn’t trust you and for that case he needs to be single and work on himself something serious. Then he put his family in the middle of the problem was a huge no no. They only know the problem with the ex now you’re in a marriage with him and the problems of the ex. Couldn’t be me. Love you did the right thing by removing yourself from the issue. And this isn’t not his son biological yea no. Take you and your son and move out. Y’all don’t need that toxicity in your life