please comment i need ya'lls advice people!

ok so i go with this guy right?...i really really love him and there's this girl (who's supposibly my best friend) and she's telling me all this stuff about him being with her and he's playing me and he doesn't really love me and all this...but she's his ex and she still likes him...could she be trying to break us up or is she telling me the truth...i mean is she letting this guy come between us? idk please comment and help me please.