Is he cheating or likes her? What do I do

Girls I need help.

Ok so basically I’m fourteen and so is my bf. We’ve been together since December last year. But lately I’ve been questioning he loves me or is cheating on me. Btw “her” is my friend that I think he likes. So He Is Playful with her and He Like Is teasing her in a flirting way and if I ask do U like her he goes no and Quickly looks away and avoids eye contact... he called her pretty and He talks to her about his problems more then me and he doesn’t let me go near his phone, like he always Says NO GIVE ME BACK MY PHONE NOW

Please help and what should I do?!?! COMMENT WHAT TO DO