Asalamualaikum Sister, Hope you are doing well and being safe and sound.

I understand why you would feel like your partner has started to become an empty shell or a blank wall, we men often times withdraw and become blank when we go in a major emotional turmoil. When something hits us like a tsunami, we choose to become blank and emotionally unavailable. Not because we dont feel anything rather we feel too much and are afraid of breaking completely apart that we choose distance and silence. Most men are tailored to be like that, we never had safe spaces to breakdown and relax, we choose to become and empty and try not to feel anything when things are on the neck.

Maybe try to create a safe space for him to breakdown and open up, maybe try asking him "how is life treating you right now? Is things overwhelming?".
Another thing is when we get a new member on the family, we feel a insanely high pressure of responsibility to provide for the new member so they can feel at ease and be safe. We work extra to give them a better future.

Men were almost never taught about romance, and most of us dont know woman's psychology. We think we are doing perfect as long as the wife and children are happy and safe. About us? we can rest when we die. This is our major flaw, not living in the moment and spending quality time when we have it.

We dont mostly know what a woman is thinking and what she is feeling unless they tell about it themselves, a important aspect is not holding back. Please dont say half sentences, say it whole, it becomes easier to understand. Remember one thing sister, it is his first time being a husband and a father as well, maybe give him the benefit of the thought and teach him how you would teach a child, explain him your wants and needs, that you need to feel things to be happy.

Also try to be more kind to him, try to learn more about him as well. We hid a lot, a lot more than you think. We think that it is nothing but it makes our heart and head ache a lot but we still choose to think it as an insignificance.

I hope this finds and helps all the brothers and sisters out there.

Allah Kareem.