Advice for coping with my boyfriend's ex wife and their daughter?

I am a 20 year old in desperate need of some advice, opinions, and help. This will probably be a bit long, so for anyone who takes the time to read it I would like to say thank you, it means a lot to me. My boyfriend and I have been dating for around 10 months now, which isn’t very long but I do have strong feelings of love for him, as him for I. He is 20 also and has an ex wife and a 2 year old daughter with her. He got her pregnant, and says she conned him into marrying her, which is irrelevant, the point is they married. Anyways, I didn’t know about the ex or the daughter until after I had gotten to know him and realized how much I like him. So even though I’m young and didn’t feel I needed to deal with his burdens, I didn’t want it to hinder how I felt about him. I know that everyone makes bad decisions sometimes, but that shouldn’t hurt them forever. So I accepted and dated him anyways. Now, I’m having/have been having a lot of trouble dealing with his ex wife and accepting the both of them. He sees his little girl every weekend and then some days when his ex needs him to watch her, and I absolutely love her, she is the cutest thing and I always play with her and talk with her and she seems to like me well. Still, sometimes I feel a twinge of jealousy when he is spending time with her and I have to remind myself that their bond and love is much more important than I am. It’s still hard sometimes and I feel sad. I never show or would show any sort of animosity towards her at all. I would never bad mouth her mother or any thing like that. I just really try my best but I need some encouragement I guess. The ex wife on the other hand, is…a raging lunatic to put it seriously. She is always yelling and cussing at my boyfriend and telling him how worthless he is, almost every time they talk. She will call just to ***** him out, and even does it nearly every time they trade off their daughter, right in front of her. She says he doesn’t help out at all, when he clearly pays child support and keeps their daughter as much as/more than she does. Not to mention when they separated he gave her EVERYTHING they had, which left him in the basement at his mom’s house with not one thing that he owned. On top of all of this, and how badly she treats my boyfriend, she still calls and bugs his sisters about how much she is still in love with him. My boyfriend just wants her to be out of his life and only converse about their daughter, but she is very uncooperative. He tells her this all the time and that she needs to be more mature about things but it is useless. I really dislike her, not just because I feel jealousy that they we’re married and shared a child together, but mainly because of how badly she treats him and in front of their daughter to boot! On the other hand this woman HATES me, and bad mouth’s me to people saying trashy things, despite knowing nothing about me. Which doesn’t really bother me because people who do know me, know me, and that’s all that matters; it just shows how juvenile and pathetic she is. I just get overwhelmed sometimes and feel like I’m stuck in this awful predicament. I feel like I’m too young for this and not ready to deal with a crazy ex wife who will have to be around for years and years to come, or to help them raise their daughter. Yet at the same time, I would hate to have to leave my boyfriend, I want things to work out. Sometimes I think about marrying him one day, it makes me happy and sad at the same time because I want to share my life with him but I know it won’t be his first wedding and I feel like it’s not as special as it will be for me. Or if we have a child together one day, would he love it as much as his first born? Would the experience be as moving for him? It eats me up and I feel like I should get out now because I’m having trouble accepting all of these things, and even like it’s unfair to him because I would want him to be with someone who CAN handle all of his baggage. But still, I’d hate to leave him. I’d hate to leave his little girl. Help, please.