I see cheating. what do I do?

maybe you should tell her to talk to him, or talk to her yourself about the situation just let her know
that what if she does decided to do anything it because she really likes this kid and if she likes
him that much maybe she should just be with him and leave the other kid alone, and if she
chose to do something and stay with that guy 2 make sure she is prepared for whatever happens
and only now to blame herself if the situation gets bad

he needs to know about her. she is your friend but still that's the worst thing is to see someone doing something that could hurt another person

NO ITS NOT. you need to talk to her and see what's going on. you don't want to not tell them because if he finds out that something happened plain and simple he's gonna wish you told him before so that way it doesn't break his heart knowing they were going out during it and she needs a brain check to not cheat people are going to judge her for the rest of her like so I think you need to talk to them both its the best you can do be a TRUE friend to him and let her know that its wrong to do such a thing like that and it is your business she's your friend isn't she and she's in your life which is your business? do anything to not have her make that mistake because if she has a good guy then he deserves more if this is what's gonna happen and help him to show your friend that she can loose something that is amazing and she needs to hold on as tight as she can.

I think that if it is bothering you, you should say something only to her. Sit her down and explain that she needs to be aware that if she continues, she may lose her boyfriend. She hasn't cheated on him though, she's just very flirty. But I still think its a little unfair for her boyfriend being all loyal to her, that she isn't doing the same for him. Just talk to her, maybe she doesn't realize what is wrong from right. ._.