What do to if your bestfriend loves you and not want to be in a releationship with you other den bestfriends?

hey i have this huge problem to solve and i don't know what should i do about it? i have a guy best friend since i was 13 and now me and him are 22! pretty long time eh. We both are very close to each other like share every single thought and memory doesn't matter if its too personal or too boring or too exciting.. its almost feel like we are married but don't live with each other. we can't live without talking to each other. and we both know we both have feeling towards each other but it was hard too spit it out. he would come and tell me he m his best friend and he does not think any thing bad abut me but still he see's wet dreams of me and em havin xxx. One day he came and told me how he wants to be back wit his ex which just made me shocked for a while. i asked me y would he do dat? he said i wanna be back wit her so u don't think bad abut me!! i feel for u ur face turn me on sometime he feel like having physical relationship but at the same time he tells him self no she's my best friend i can't lose her by betraying and having physical releationship! so i asked me why do u wanna be with her? he told me how they had physical reletionship with eachother and he feels for her but he feels for me too he doesn't want to c me hurt or cry! he says ur the only person i can share all my feeling wit be free witout even thinking ur a girl! i care alot abut you and can"t afford to lose you! i told him how i feel alot for him but if he wants to go out wit her i won't have no problems wit it but he knws how hurt i am frm inside and he feels guilty. he says dont change be the same u were! i am trying my best but after he told me m like 100 X more in love with him but i dont want to ruin his life! JUST NOT SURE IS HE GOING OUT WIT HER TO GET RID OF FEELING HE HAVE FOR ME OR DOES HE REALLY FEELS OR HER! HE TELLS ME I HAVE ALOT OF STRESS IN MY LIFE AND I DONT WANA BE A STRESS FOR YOU! i love him lot i just dont know what to do be a same friend as i was :( will he ever come bac to me ?? i dun know if i can falll in love with someone else!