What do I do

I had a crush with this guy he was for the perfect man. We never dated and I never asked him because deep down I knew he didn’t like me. Or he did but only as a friend. He started dating this girl she I not a friend but she is a nice girl. One day he gave me his invitation for his wedding. Now I’m in my room crying and I don’t know why I feel this way. I knew he doesn’t like me I told myself I don’t like that he will never de mine I need help advice.