What should I do! I did I make a fight?

Well this happen at school. There these to friends that are boy and girl . But they fight and yell and stuff . The girl is pretty popular while the boy is kinda strange . Well I knew him since 1st grade . She knew him now . 6th grade . Anyways at recess he said I was his best friend . Then at lunch the girl comes up to me and says " Did you steal my best Friend?" I just No ( I didn't want to put up a fight). Even though the girl is nice to me .At out lunch recess they were playing and fighting at the same time . He told me he was trying to make her jealous. And then during cl she was pissed off . She wouldn't talk to him . I Just think hopefully they would get along . What I need is advice or tell me is it my fault ? Should of I did something else?