He is always on my mind

tHERE IS HIM THAT I USED TO LOVE SO MUCH , I loved him for 2 years but i never let him know ,and i also knew that when he wass in a relationship with a gurl,he was never serious but then he finally came to know!After about 2 months, he askedme out because he told my sister he really love me and this time it was for real (he was my sister's best friend) i was also assured it was for real because for me , he left the gurl he used to love more than his life . we went out for one month , then we finally broke up & the reason he gave me was that he still loved me but his Dear cousin brother was also in love with me before we went in a relationship , despite knowing that i loved onlyy him and not his cous, all this hapened! now,we broke up and after enormous efforts we became back friends!After loving him so much,all this time ,,i want to forget about him but i can't because im always missing him,he is always on my mind,i see him everyday at school its just so dificult to get over him I really wanna forget him but how?i always have the feeling that its now that he'll call,,everything will be okei again ,i'll be happy again,he'll love me for real & i keep assuring myself that i don't love him buttt i can't just get over him,,whenever i see him spending good time with another gurl , I just get jealous & this can even spoil my whole day :O But why??? i really wanna get over all his , please help me out :x cause i'm just lost!