Off topic OP.... Your mother has done a number on you emotionally. Have you ever had counseling? I think you would really benefit if you haven't.
I think your hubby should speak with your in laws about caring for him when you are gone. It's not like he will be driving to drop him off and pick him up daily , so the hour drive is no biggie, if they can keep him.
You seemed to have a huge heart and giving spirit. Just a all around great person (here comes the but..), but really evaluate why so many of your relationships are toxic. Relationships shouldn't be this hard and difficult... if you are in many toxic relationships at some point you have to start looking within as well... You grew up in an abusive home, therefore you are bringing your hurts, insecurities, and fears into other relationships..
What's up with wanting to leave DH? And I need to look up gut bucket...
ETA: I just looked it up, your mom was disgusting for that, keep her out of your personal business. You have us to vent to.