I think I am losing a friend

I am a boy and now 17 and in the final year of my school in germany. I know my bestfriend (f 17), since she was in the first grade. We always had a good relationship. But a few months ago we had a really close relationship. I dont have any feelings for her, but we could just always hang out. We went walking at night at least once a week. We always talked about our crushes and stuff like that. And we both said that we would be best friends forever. But then she got a boyfriend. And now everything is just a bit weird (cause i'm a boy and she's a girl). I am also good friends with him, but it now feels awkward beeing by her side. We never saw each other outside of school, since they are together. Im too shy to ask, if she wants to hang out, because I think she could say no and distance herself even more from me. And she always goes to him and im just left there alone. I think she deserves him so much and I feel guilty, because I want to spend more time with her. I cant talk about this with my parents, because they would not take it seriously or would be disgusted of hearing that I have feelings. Everybody always wants me to act like a man, except she. But I dont know how I can not lose her, without hurting her.