Congratulations!
Pregnancy, for me, was a trying time for many reasons. One of those was that my marriage (then relationship) was unstable and I felt chaotic. Anyhow, I REALLY relate to your description of shutting down.
Here's what I am learning. It is NOT an over night process. Shoot, my last question was indicative of how much I struggle with learning/internalizing these tools. However, I get great relief when I'm able to use 'em.
1. It's okay to feel. It's healthy, normal, and human. Feelings are simply chemical messages passed around our body. It's helpful for me to draw parallels between physical pain and emotional pain. Both are in the body and are temporary. They are my body's way of telling me something is off. "OUCH, I just cut myself, it hurts and I need to tend to my wound," or "OUCH, I feel resentful and I need to tend to my wound."
2. *I* am not sad. I am FEELING sad.
3. Non violent communication. It's really helpful for me. It is tedious, cheesy and sometimes exhausting, but it works. For example: When you ___________ (ex. cuss at me, don't take out the trash, make phone calls during dinner), I feel _____________ (sad, angry, lonely, frustrated, hurt, confused, threatened, distant, etc.).
4. This is what I REALLY struggle with. Let myself feel. Take space to do it. I don't need to dwell on it, nor do I need to push it away. I can simply let it wash over me, see it, note what it feels like, where I feel like, ask what it has to tell me (I don't always get to know right away...or ever), and then be willing to let it go when it's time. Feelings are not logical. They are not on my time frame. That, for me, is challenging. I am sometimes overcome with grief, for example. It's simply not realistic to always let myself be fully present with that feeling. So, I'll note it, and then later, try to make myself available to not struggle against it.
5. Self care. Eat regular meals, do enjoyable, rejuvenating things, be open to connection, have gratitude, *ask for help* (I'm learning this as I go).
6. Not asking others to fix it for me. Your husband sounds like he's doing a good job owning and being accountable for his actions. Hopefully, he's not just apologizing but is also changing his behavior. This takes time and is messy. You get to have feelings. An apology does not mean you have to shut down your feelings. For example, my husband just REALLY messed up. Last night. He's apologized no less than five thousand times. This one is going to take me a while to move through. I've said, "I know you are sorry, thank you for your apology, etc", so that he knows I heard him. I've also said, "This is going to take me a while to move through. I am having a lot of really big feelings come in and out. I will need space at times. That's not to punish you, it's so that I can better take care of myself. You will need to know that I am not capable of being your only support person/system." He IS sorry. And I STILL have feelings. Also, sorry is a word. Action is an animal of a different color.
Big, big, big hugs. Good luck.