My best friend is dating this really great guy..and I still like him..?

Ok so I met this guy awhile back ago and I liked him and he liked me. All was great until i introduced him to my best friend. Then he started liking her and she liked him back. I was really hurt at first but I moved on. Well now they are together and completely happy. They even tell each other they love each other..which makes me completely miserbale because I realized I still like him. I am glad that they are happy but I feel like I got him stolen from me in the fist place. What should I do??