Is it fair if I continue not speaking to them?

Since being with my partner his family has never made an effort to see us it was always me and him going over to see them which did my head in, we have our own house they can come to and what’s so hard about organising a day out? Go out for dinner? Go to a park for a BBQ? Me and his sister have had massive arguments about this and nothing changes, So during my whole pregnancy my partners family didn’t care at all, it upset me alot but my partner was sure it would change once our son was born, skip to nine months later I gave birth to our son and His sisters, brothers and mum came to the hospital to meet him which was nice. But since then I’ve been the one contacting them to see if they’re free, they don’t message and ask how he’s doing. They don’t make plans. They don’t care at all, I send them pictures and updates of our baby and no reply. Can’t even call to see how he’s doing. I was going over their house a lot after he was born but then it got to the point where I’m sick of the only one putting in the effort, why should I have to drag my son around to their houses if they have cars and a phone? I haven’t spoken to them in a couple of weeks and of course I haven’t heard from them at all. I don’t want to talk to them anymore, I’m not cutting them off but I’m just not putting in the effort anymore. My partner seems to not care at all but I didn’t grow up with family so I want that for my son.. is this fair of me? It’s a one way street and it’s supposed to be a two way street.