Loving someone that doesnt love you the same? how can i let go?

i really have a problem and i need some advice on how to let go!! please talk to me?
ok im gonna try to keep it short….me and my ex have been back in forth for 4yrs and we are almost always breaking up…..but the very last time we broke up he begged me to give him another chance..and i did..so we were good for about 2months and then he fliped out on me again…so now im back where i started but man I STILL LOVE HIM SO MUCH`i dont know how to let go…we have a 9month old together also…i be so curious to know who he’s talking to that i even snoop on his fb page in read all his post and this one gurl he told her that he loved her and MISS HER AND he dont talk to me anymore he dont care about me anymore….but he was just trynna be with me a couple days ago….I’m so hurt and feel so disrespected and i dont know how to let go. he obviously dont care about me.

how can i learn to let go of the stalking his page?
and learn that he couldnt have possibly love me to think of me like that?
this is my 1st time falling in love like this and i was so good to him?
i find myself sending him messages on facebook, asking him why would he do that to me
i just wanna forget about him but don’t know how