My friedship with my best friend is ruined? Please answer?

To make a long story short, the first time my friend met my girlfriend, he caused a scene because he was so jealous. It turns out that he really liked the girl that i am dating, but he never showed any interest in my relationship until this happened. He knew who i was with because i told him, but three months later, when he wants to see for himself if it was true that i was dating this girl, he flips out on me. He never told me that he liked this girl, so i never knew, if i had known, i would have never made a move with her. Plus, THREE months later, he decided to start caring about it, when i told him i was going out with this girl the day after we started going out. So, i tried to apologize to him and say that i did not know that he liked her, which i really did not know. He said the only way that he would be my friend again is if i break up with my girlfriend, and i refused because i have developed strong feelings for her. Who is right in this situation? I think i am because he never told me that he liked the girl, and he started caring three months into our relationship, when he knew i was going out with her right from the start. Btw my friend and i are both 15, and my gf is 16, if this helps. I posted this question again because i was unhappy with the answers i got.