I live above my in-laws and his family never comes to visit, why?

Hi everyone, I have a question that's been on my mind for a while. We live upstairs with my in-laws. We each have our own apartment, but we share a front door. You walk in through the front door and find yourself in the hallway with my in-laws, and then go up the stairs to ours on the left. And from his side (he has four siblings), no one ever really comes to us. They're friendly when we visit them or when we meet downstairs or outside the door, but almost no one ever comes over for coffee. What's the reason for this? There were a few problems with his family, for example I am a part-time/nude model as a hobby, or used to be, and my mother-in-law and sister-in-law couldn't really deal with that, but in my opinion it's none of their business. At our planned wedding at your place when we wanted to take my name, there was a huge argument (involving my mother-in-law, her favorite son, and her favorite sister-in-law), and they said we would have to move out if my husband changed his last name. In the end, the wedding was called off. I keep hearing that the same sister-in-law is talking badly about me and my husband, but I don't know if the other siblings are involved too.

So now to my two questions. Why isn't his family coming? Is it because they simply don't like us, or is it perhaps because we live upstairs from my in-laws and his family thinks we'll come down whenever we want?

The second question is with my sister-in-law who gets upset about things that are none of her business and who I've heard from others that she talks badly about me and who of course never comes over (but when I do see her she's normal and fairly friendly). Her son and mine are almost the same age and therefore ideal playmates. However, I don't want her to ever say anything because of the children. What could I do?