I love a man who is in a relationship?

I really love this man who attends my university. I know him from a uni club and i am also friends with his guy friend. I liked him from the minute i saw him but i obviously minded my business. Then i found out the president of that club is actually his girlfriend. I saw them holding hands in a cafe on campus. I also saw them fight a very bad fight near my workplace (on campus). I even had to tell my guy friend about their fight so he can deescalate their fight as they had a real bad fight infront of our office. Anyway i am no longer interested in him or pursuing a relationship with him since he is obviously taken but i can’t help but get feelings for him when i see him around although i won’t approach him about it. I was wondering how can i cope with this and move on from him?
I love a man who is in a relationship?
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