She's cheating and i want him

I say just tell him about the cheating since you should always tell someone if they're being cheated on. He probably already knows about your feelings so just let things take their course. You really don't want to make it look like you are benefiting from the whole situation.

Let it go for a little, see if things start to reveal by them selves because then you can provide moral support to your "future bf" without looking like the mean person (or overprotective dog). What ever you do tho, keep the bro code (don't mess with someones bf(cheat)) it never helps.(make sure they break up on their own).

Now remember that if truth comes out that she be a bitch and they break up, Don't go sucking on his D the next day, and I know it might be a big desire but he needs to recover. Guys usually tend to be mad or not give a fuck for 1 month or 2 and then they start thinking of options by month 3-5 (depends on the person(seriously it depends)). At that time be there, get to talk with him more, set up routines or something just between you two and add a hint of flirting. That shall do it... I hope. (don't tell your feelings until that point).

EDIT: just read your comment: !!NEVERMIND!! it was a troll comment (probably) Don't read below or do idk...
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if things aren't going as planned but like REALLY BAD with the girl, he might be in recovery. but as you also said he is faithful, odds are it might not work out, usually its what happens. Best solution is to wait it out, wait for it to stabilize and then start. And I'm not sure but check how deep you are in the friend zone or if you are at all. Its a good thing to know before doing moves.

Can someone help me

In the world at large everyone is a whore. Snap your fingers, take off your panties, fuck everybody. Fun times.

You need some concrete evidence before you go throwing around accusations about her or you could lose him as a friend. Also, if you decide to tell him how you feel, be prepared for the possibility feelings are not reciprocated . Better to tell him though. If he doesn't feel the same, you can move on with someone new. Good luck

He is not your game and you aren't a hunter. Tell him the truth because it is the right thing to do. If he's interested in you he'll make his move or you yours, when the time is right.

Start an ugly rumor about her. Get with him behind her back. Seduce him. Then expose her. Show how savage you can really be.

Be the bigger HO.