How do I talk to him about my anger?

[Summer]

So I dated my ex for 2 months, it was a spur-of-the-moment asking him out thing but he said yes. I always thought our relationship was going great. Things were never really physical but the love was there. I mean we'd talk for hours and hours but our relationship fell apart after i got really sick with H1N1 and had to miss his birthday. I gave him his gift (a really nice sweatshirt that he really needed) and tried to make it up with him but i was angry because he didn't seem to care that i was sick and never visited me when i was home sick even after i was deemed non-contagious. and he was angry because i missed his birthday. We're both kinda quiet so we never voiced this and things fell apart. Afterwords he told me he loved me (he never told me so when we were dating) and i regretted breaking up with him but i tried to move on. but a few months later i found i couldn't so i asked him back out. he rejected me saying he'd "moved on" and now, a few months later then that, he has a new girlfriend who's a friend of mine. at first i hated her, thinking i "loved" him but now i know i never "loved" him. but that's when i realized he's so much sweeter to her, he holds her, kisses her, he gave her a hickey, and she wraps her legs around him and they play and joke around. he cares so much more for her. and i'm so angry at him for never being like that with me. i never knew he could love like that. it makes me so angry that he treats her so much better. why?! is what i want to know. I don't even like him anymore but i just want to know why wasn't he like that with me? am i not pretty enough? is it because she's skinnier then me? why?! i don't know how to bring this topic up with him or explain it to him. I also have a problem staying angry with people for long periods of time (like even two days) and even though i'm hurt i'll probably talk to him like i always do. help?