I am almost 28 weeks pregnant with my ex's baby. She was completely planned and tried for. However, He is still completely involved in things and we still talk to one another everyday and still occasionally have sex with each other as neither of us have other people in our lives in a romantic way as we are trying to work things out and figure our own things out to be together before our daughter arrives. Well my sister is constantly talking to him and always trying to be in our business. He talks to her and tells her things then tells me he don't wanna talk about it or he didn't feel like talking about it or wasn't in the mood to talk about it. So I find out a lot of things when she let's them slip. They also hang out with one another and act like I'm stupid and dont know. But neither one of them will be honest and tell me. They text all the time also.

I'm just wondering if I'm wrong for being extremely upset/pissed off that they talk this much and that they hang out with one another. Or overreacting? Am I wrong for feeling like she needs to stay the hell out of it and stop talking to him?