What can i do about my feelings for her?

theres this girl i like but she has a bf right now. all i want is her and i feel like even if she was single i wouldnt have a chance. i always thought it sucked that shes so perfect for me but i cant obtain her. its like having a million dollars right in front of you but its locked in a unbreakable case. what can i do. Ps im not getting over her because she is litterally the most beautiful thing ive ever seen