I would engage with your wife through engaging well with your kids. She will be able to see the changes there and in your communication with her about the joint care of them. Just tell her what you are up to (the gym, support group) as you schedule time to see the kids ("Let's see, I go to my support group on Tuesday evenings, so Tuesday is out,. . .", etc.

Let her invite you back into her life instead of pushing to be included.