okay guys, i really need your help and support.

heres what happened:

six months ago, i met a guy (Toby) that i really liked but i had a boyfriend (Sammy).
i didn't want to end up cheating on my boyfriend to i broke up with sammy so that i could continue to explore Toby. he said he loved me. i loved him. we shared a few months together but i noticed that he was getting interested in my best friend (Eve). she hated toby and was really pissed at me because i had changed so much for him.
all through this sammy was still my best friend and was trying to like toby (though it was basically impossible)
after a while toby and eve started hanging out more and more, toby admitted to me that he liked eve and was breaking up with me.
after only a day he came back, saying that he still loved me. i took him back, being very grateful that he chose me over her.
everything was fine until he started getting into other girls again.
he kept trying to cheat on me with several different girls but none of them liked him at all. i was all blind to this at the time.
until about a month ago....he found a girl (Jenny) and started cheating on me with her.
i was heart broken. i know that he never will admit to anyone that he was cheating....he just forgot that he sent this to me once he found out my plot to break it off with him.
this is an EXACT copy of his email.

"I fuck up everything. Drawings, fun, love. I know no matter what, you'd deny anything I say, but I don't care anymore. I know your behavior recently was all that whore-of-a-girl Kayla's fault. But I bet you would never notice. I guess I can tell you this now. I did have a thing for Jenny. I do like her. Actually, I love her. I can probably tell you this now, but I knew the whole time I WAS cheating on you. And I feel absolutely no guilt now. Have fun with your new "friend".

See you never."

oh, and Kayla is my good friend, also his EX-girlfriend so he's blaming everything on her.

so for the past month he's been writing me hate emails, giving me dirty looks and such.
im not going to act like im innocent, i did alot of things right back, including fliping him off twice.

so, if he's such a dick, and im better off without him why cant i forget? why does my heart feel like its going to explode from beating so fast whenever i
pass him in the hallway? why do i feel a tightness in my throaght everytime i see him making out with jenny?

i need advice guys, please please please help! send me a message, i will reply to it.
thanks