Good Morning B., I agree with Ruth, there has to be more to this then the door issue. It could be a tad of jealousy with the new baby. If your oldest is 4 he had some of your time. With a new one you are busy again.
I also agree that it may be time to try finding a place of your own. Our son and family lived with us from right before they got married until our second gr child was born in 2000. Way past time for them to hit the road. That gr son will be 10 in Aug.
It is very hard to be a real family when living with in laws. We had to stay with my mom for 3 days and it was the hardest 3 days, I have ever had. Our son was 6 months at the time. Our septic tank was being replaced in our rental and it was close to gas lines. We didn't have a say what we did with our son those 3 days. UGH!! Plus I had to cook and clean up after everyone. Just like being a kid living at home again.
Your husband may feel he has rights or say so it's not his home. Like Ruth suggested if your not caring for your mom for medical reasons, I think I would sit down and talk to your hubby and see if he is ready to move on to your own place. Doesn't have to be far away, but some place he can work on, hang things on the walls or nail something in the garage. Men need to feel they are important and needed also. Right now I am assuming he doesn't feel as if he is providing for his own family.
God Bless you B., gives you something to think about.
K. Nana of 5