What to do!?

Okay.. so my fiancé and I have been together quite some time. I have two children from a previous Relationship.

My fiancé an I go way back so when we finally gave it a chance it was no doubt this was right.

He treats me kids as if his own, and I respect and appreciate that. His family did too. Till we had a few fallouts.. they become super disrespectful towards me and cut me off. Blasted me all over social media made fun of me and just allowed ppl to laugh on my name... they allowed my fiancé’s EX girlfriend to laugh at me too. Now that got me to my boiling point!!

Fast forward... still rocky with his family.. I’m currently pregnant due soon.. and his family just thinks they are obligated to be here and they have the right. As his family I agree but after disrespecting me!? When do I become a priority here at all. I won’t allow people to just walk over me and think its okay. I have two other children to think about as well!! Anyways so come to find out his family decided to keep my fiancé’s ex girlfriend in the loop. They now chit chat all the time and my favorite just had her over for dinner and wine. UM HELLO? Ex girlfriend? I’m the fiancé here... I’m carrying your grandchild.. I’m the one your son chose to start a family with here. Do I have a right to be upset?