Love him or leave him? what should i do?

for more information ,like this ,before that i give their name first .the guy that i'm talking about name's M and his bestfriend's name A .okay i'll start now .i was waiting and loving for M who has nothing special at all .he is also my bestfriend's ex .i've been waiting for him about 3 years and still counting .and that was since i met him at secondary school .last year holiday ,i chatted with him and we get closer and closer and get to know eachother better .so as i was also closed with his bestfriend 'A' before i met him ,i asked A does M like me? and A said he really like me and love me and also wait for me .i was kind of shock and confused .he ever told me that he loved me but i'm just laughing back ,i didn't took his words seriously .and i thought that he just want to play me .for about 2 weeks after ,i gave him my private blog and those blog is fullllllllllllllllllllllll about him .i just wanted to make him understand but he didn't btw .i was soo so dissapointed and sad .i thought after that he will realize the same thing to me but NOT .all the thing he said was just 'i really love you' .then day goes by and i flirt with his friends and seniors in my school .well ,i tried to make him jealous and i asked A does he jealous? and yes he does hahaha .he didn't text me for about 1 week? yeah it's kind of stupid things ,ignore it then .then we get closed back but this time ,he didn't seems like who he is .he didn't treat me nicely ,i thought he has another girl but i don't think so then .hmmmm i just want us to be happy like the way it was ,i want to make him mine .i really love him and i don't know why .help me pleaseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ,give your answers as long as you can like my story does okay? haha