boyfriends cheating on me.....idk what to do now any suggestions? :(

It would suck if you broke up with him and then found out that she was lying.

You should talk to him and see what he says. You have known him long enough to know if he tells the truth. Even if it is true, it is not your fault.

Okay, let's say it is true. -
If he would do that with her, and to you, he isn't the kind of person you need in your life and he doesn't deserve you in his life.

ok...i juat talked to him and we broke up and he still wants to be just regular friends but i still love him and im having an anxiety attack and i just wanna die........being single is heart wrenching

From : The Rose

Some say "Love. It is a river that drowns the tender reed."
Some say "Love. It is a razor that leaves your soul to bleed."
Some say "Love. It is a hunger, an endlees, aching need."
I say "Love. It is a flower. And you, it's only seed."

all of that is true

Precisely. That's why one should confront the boyfriend with these allegations and try to suss out whether his response is truthful or not.

What you NEED to do, is sit down with this boy and ask him IN PERSON if he has indeed been sleeping with this other girl. If he has, you need to cut ties with both people and you need to work on yourself. What I'm about to say is going to sound cheesey but I've been where you are now. You need to learn to love yourself. You need to find what makes you happy but it has to come from YOU not other people, certainly not boys.
If you break up it won't be the end of the world. You'll need to pick yourself up from your bootstraps and show YOURSELF how strong and awesome you can be. It sounds like you may have a low self esteem and the wrong people will prey on that. Find good people, people who are kind and truly care about you.
Most importantly, take care of yourself. Drink some water take that nap, pamper yourself, have a treat.
You do you boo and the right people and the right boy, will come along.
Take it from a former depressed and suicidal teenager.
I'm now happily married with someone who makes me laugh everyday.