I'm in love with my ex boyfriend who now has a girlfriend but he is part of who I am.

I'm 16. I know some people can be dubious about age however please don't doubt me when I say I am truly and deeply in love with my ex. We dated for just over 9 months, he is my first love and was also my first sexual partner, we broke up 5 months ago now and he has a new girlfriend but my feelings are just as strong as they ever were. Within the first couple of days of dating I had 2 of my closest friends die in a car accident and was also diagnosed with a life long medical condition, he supported me through absolutely all of it, within a week I was head over heels.
Our relationship survived through long distance and other people trying to break us apart. We were inseparable, every day I spoke to him from the moment I woke up to when I he would talk me to sleep at night.
He was my everything, my reason for happiness, our personalities, our life styles, our bodies, everything about us just fit perfectly together. He was my prince charming and he treated me like nothing but royalty.
But at the end, he had alot of problems with some deep set depression and basically baracaded himself emotionally to the point of where we were like a shadow of what we used to be. He broke up with me soon after saying I deserved better but he loved me with all his heart and wanted me to be happy.
For the next couple of weeks we tortured each other in arguments because I so desperately wanted him back but he said he couldn't go back on his decision. Then finally he used anger to get the point through, he told me I was a lost cause and to please leave him alone. I did. We didn't speak for a long time. It killed me every day. I had allowed him to become a larger part of me than what I was, I'd just lost the most important part of my life and I felt so empty.
My life has spiralled downwards since our break up but my feelings remain the same. I've had a multitude of opportunities with other guys, but I can never let him go, I promised my heart belonged to him. And that is a promise that I can't break no matter how much I want to or how hard I try.

Please. I need unbiased opinions, advice etc.