Boyfriend issues

Hey guys so I've been with my boyfriend for a year almost two now and it's only recently that we started fighting on and off for the past two-three months now. We having been fighting over stupid things too.. And today he finally admitted to using mind games with me and guilt tripping me everytime we fight so I'm the bad guy everytime. And he also told me he is very insecure about our relationship and when we fight he suggests breaking up and if we break up we will never talk again. Actually as I'm writing this he has just texted me that when he was in the shower he almost cut himself but cried instead of doing that. Because of our fighting so constantly I've kinda had a wandering eye and have low key developed feelings for my friend whom I've been close with for 5 years and without fail I've had fun with every moment we have hung out. Now as well as all this but everytime I hang out with my friends whether be guy or gal without him he acts weird and very bipolar towards me and rejects my kisses or hugs. I just don't know what to do anymore. My friends say break up with him but I can't bring myself to do it. You guys I really need your opinions and advice. Him and I are only 17 and are juniors in highschool.