baby momma drama😒

Okay, so I'm in a relationship and previously before we werre together he was with his ex and she got pregnant. But she cheated on him and this and that so he finally hit the point where he was done with her. So then he started renting out guest house on our property and then next thing you know after awhile we started liking each other and started dating. Then before his daughter was here the baby momma was still blowing up his phone, won't leave him alone. "Claims" she doesn't want him or love him anymore but constantly talks about them and how she wants him. Then she kept saying "is" and "we" thinking because she had their daughter that he would come back to her. He clearly doesn't want to b with this girl. But she's CRAZY!! She blows his phone up all the time and Facebook. I trust my boyfriend and Ik he's not doing anything because I read their messages. He just avoids whatever she's saying and asks to see his daughter or what can he get her. But she's so jealous over me it's crazy. She freaks out abt me being around the baby when I've raised twin premie babies( sisters) I've been around kids my whole life but I think it's more of " you can't b a family with her" type of thing. She's always saying the baby isn't nothing to me and won't ever b. But me and my boyfriend are getting married and trying to have a baby of our own. So I'm obviously not going anywhere. I'd never treat the baby any different. The mother is always talking shit abt me and just being a straight up B I T C H!  She doesn't leave my boyfriend alone either. She acts like she has to talk to him everyday and it's not even abt the baby. She even pays his phone bill twice and he didn't even kno until he went to try to pay it himself. Can anyone please help? I don't want to cause a fight between me and the girl cause I'm not pathetic and petty. Me and my boyfriend have went they so many conversations and arguements abt this because she won't stop. Does anybody else deal with this ?