boyfriends baby mom won't accept me

Ni
Me and my boyfriend having been dating for almost two years now. When we first met I was dating someone else but not in a relationship and he was seeing his baby's mom but not in a relationship either. We took things slow. I stopped dating other guys and he put a end to their so called relationship. Me and him became a couple. Now it's been 1 year later of just us together with no one else in the picture. We are moving in together and I still have yet to meet his daughter. It was always an excuse like he wasn't ready. Or he was unsure if I would leave him or not so he didn't want to bring his daughter in to our relationship. Which I totally respected and understood. Now that we are moving in together he wants me to meet her however when he told his daughters mother she was not having it. Saying she didn't know me, she doesn't want to know me, and the little girl wouldn't be allowed at our house. I don't get it tho because she's constantly complains about how she gets no help and she's a single parent. Btw he says she was never his girlfriend just a girl he was banging she got pregnant and he tried a relationship for the baby's sake but he just couldn't because he didn't love her. So why do this??? Why not just get over him and stop being spiteful. I just don't get it. I know how much he loves his daughter and that makes me want to meet her so I could love her too. I would love for him to be able to see her more and we could all do things together. Like what am I suppose to do? What is he suppose to do? He says he doesn't want to start any drama.