Baby daddys girlfriend WONT ALLOW US TO TALK

I have newborn baby with my ex pf 1yr 8months he just started datinga girl but she will not allow us to talk. I cant call text nor send pix of the baby he can only see her on saturday for a while whrn he comes here and shes always calling. He pays child support. But this situation is so stupid i feel like i was the mistress and my child was a baby he had with some side chick. Smh. How do i deal with this? Me and my ex are on friendly terms. When he needs a favor he has to call from his friends phone with out her knowing. And if we bumb into each other he cant even look at me. Btw his new gf is older than me and him so its so stupid.