Am I overreacting?

I've been with my boyfriend for going on 5 years. We have 2 kids together and he has a daughter from a previous relationship. My problem is that his whole family does not include myself and my kids in anything. Has not seen my son since he was 1 who is 3 now and has never met my daughter who is 2. But they still see his other daughter on a regular basis and gets her stuff for every occasion (birthdays, holidays) but my kids never get anything. Thanksgiving this year my boyfriend and his daughter went to his moms house but my kids and I were not invited. I have told him many times that if his family doesn't want to see all of his kids then he shouldn't let them see his daughter either but he sees absolutely nothing wrong with what's going on and often tells me that I'm the problem. His daughter is 9 and will come back home and brag about these grandparents that my kids have no clue who they even are... I wouldn't let the grandparents keep my son (without me being there or overnight) because they'd always brag about "beating my boyfriends daughters ass" when she was bad and sorry but I'm not leaving my kids with people like that. I never once said we couldn't come visit or them visit us but they were that salty about me not letting them keep my son that they haven't seen him since. I think my boyfriend should step up as a father and tell his family if you can't accept all of my kids then you don't need to be in any of their lives. Am I overreacting?