Baby Mama Drama

So. I'm dating this guy and I have been for about 7 months now. He has an almost 2 year old baby that I adore so much. Well, when we first started dating his baby mama wanted to meet me.. When she came over I politely introduced myself, and she totally ignored me and then used some lame excuse that she came over to see her kid and not to meet me. And that wasn't the case, I heard the conversation. She doesn't have a good job, and she lives with her grandmother.. Her child's shoes were too small on him, and I bought him new ones and from then on she's been having this stupid shoe war with me. It's totally ridiculous. She's also made some indirect snarky comments when I'm standing right there, and I just ignore it for baby's sake, and my boyfriends sake as well. ( I do not take sh*t from anyone, so it's been hard to bite my tongue.) She stomps all over my territory.. She's just not nice. I don't get what her problem is. I've tried being nice, putting myself in her shoes, giving her the benefit of the doubt, and now I've just had it. Like wth? Advice? anybody? Mind you I do not have a child of my own.. Is it jealousy? Or because of her kid? What? Just sick of the drama. Wish we could be civil at some point. She's driven me to the point of avoiding the exchange at all costs because I can't stand to see her face.