Dear Lizzy:
My first suggestion is to no longer have fights with him, not small fights and not huge fights. None. It is possible for you to be assertive and not aggressive. Notice you wrote: “When I’m mad at him he is nice”- not a good thing, scaring someone into being nice. It works short term, for you, but harms long term (just like the drinking and smoking that you quit… congratulations by the way!)
You may figure that living with him is not working for you, but first, no fighting. Then figure it out.
I assume without smoking and drinking, without that thing-to-do when particularly anxious, you are left with the anxious and nothing-to-do.
Except that there is something to do, something new to replace the old. A new habit to form. What will that new habit be? That will be up to you to choose.
anita