OP, I truly hope you follow through on staying home (or taking a nuclear-family-only trip) for both holidays.
I find it interesting that despite being in therapy your husband still seems to feel obliged to spend holidays with his dysfunctional family and doesn't feel strong enough to just say no. Please consider talking with him about exploring that with his therapist. It would be worth finding out why, after he was "thrown under the bus" and abused as a child emotionally, he still feels some kind of obligation to "go home" for holidays, and he might benefit from working through that, as might you.
I hope you can get past your fear of repercussions and being made the bad guy over staying home. You do not owe that kind of guilt to either side of your family.
One tactical thought: If someone says, "Oh, we'll come to you, then" (maybe despite the cat thing--other relatives might try to foist themselves on you), be prepared and have a script firmly fixed in your head in advance: "Sorry, but we're going to have a low-key holiday here with just the three of us and some friends here in (city). Traveling is not in the cards this year." You don't want to be surprised and then end up saying, "Um, uh, well, maybe for just a few days, OK...." when you really do not want to see these people at all. They may not suggest coming to you but if they do -- be armed with a rehearsed response and be sure your husband is ready and rehearsed too. They likely will hear YOU say "We're staying home/We're not having guests" and then turn around and call him to try to get a different answer.
If they then huff and puff at you about "being selfish" (a classic, and it sounds likely that these relatives would try it), be sure there's a big smile in your voice where you very pleasantly say, "I'm sorry you feel that way and I hope you'll have a good holiday. But we've made our plans and they do not involve traveling or hosting." Then Change. The. Topic.