The girl I like is with some other guy what should I do?

I really like this girl and I hate her boyfriend she loves him I hate him cos he is an *** to me shes told me she likes me then I asked her out one day she said no cos she lives really far away well her boyfriend lives like 3h more then where I am I guess what im asking is how do I stop feeling like crap when I see them together I think when ever I try to hang with her he never shuts up about how hes better then me that hes with her and im not I wanna knock his teeth in im sick of him I cant hang with her any more cos shes always with him shes even starting to forget about me she said oh yeah come to the mall with us I was waiting to find out what time and she never texed me she said she forgot to tell me shes a really good friend I dont wanna lose her I dont care about going out with her so please tell me how I can be her friend again