I can't seem to get over my boyfriends past with his past 2 girlfriends. I don't know what to do. Can anyone help me?

Erm... sounds like you're going to have a few problems then. Unless he brings them up, or they are active parts of his life... its your problem not his.
Odds are you're letting yourself dwell on this subject, and let yourself think about things wondering when or how he did this with her. You need to teach yourself to cut those thoughts short.
When you start to think of something like that tell yourself "NO I refuse to think that"
Because truthfully its only hurting you, and in the long run it will hurt him also.

PS: maybe later you could put a little more information into your posts?

Hello, I am in the same situation and I also need advice.. more than "you're jealous and it's your problem" because I've heard that and 'get' that. I just can't control how much it bugs me. I myself don't know why. I just can't help but feel as though I'm '3rd' in line or something. I know they are 'ex's for a reason or whatever, but what if he isn't necessarily the one that chose that, so maybe he still does have feelings for them or something. I have tried to talk to him but he just tells me to 'leave it alone'. Even when I try to explain reasons I feel like this (he asked one to move in within a short time, moved the other in as well, took them to football games, to hang out with his friends - literally does NONE of that stuff with me). I am 5 years older than him (28-23) and am a beautiful and smart woman who has dated men who are very successful and better looking (he is still a student) I don't say that to sound *****y, but to emphasize that I'm not a woman who has 'these' feelings and am generally very confident. It's almost like he doesn't make me feel confident anymore... Adive PLEASE!