i need advice, help please! its about Exes and stuff, sorry if you think this is pointless, i just need to moan

Well a week ago i got a message from my ex boyfriends other girlfriend, saying that hes cheating on us and she couldn't believe it, so i told her all i know, then she starts calling me a liar saying I'm trying to break them up, and I'm like Wtf :S and he keeps telling her that I'm nothing and i was just there and that I'm lying too, and i figured out that i obviously wasn't important, so i leave them alone with it and decided not to talk to them anymore, and completely erase them, and today Ive finally just started to get over him, and he phones me saying hes asked out my best friend and shes said yes.
i only answered because he threatened to kill himself if i didn't,
but why would he want to tell me that?
And i feel annoyed at my friend for saying yes, i mean i don't want to hold her back, but she knows how i felt about him.

Just gotta say, this wasn't a meaningless thing, we were together for about 2 years which is even more upsetting.

OH and get this! when i first found out and asked him about it, he shouted at me for accusing him of cheating.

i know not all boys are like this, but its kinda hard to cope atm, sorry i know I'm just moaning like a complete psycho bitch, and when i just read it over i seem like a saddo, but I'm not, I'm just trying to understand it ha ha, so what do you all think?

Sorry again for moaning, i don't do it much so when i do i do it ALOT =] x