When my dad left (some 40 years ago) my mom made "you and me against the world" our theme song and she said that we (my sisters, me and her) were a team and we would be just fine.
Maybe you can have DS help you pick out a crazy power song and either one of you can start singing it or play it whenever you want to remind yourself that you will be fine -- together, the two of you.
If husband wants visitation, Maybe you can get it ordered that it be supervised by the therapist. Dad seems like he needs the professional guidance.
