How do I get out of this constant thinking and dreaming of my ex Narc??

My fiancee was loving and caring up until 2 days before he moved out, when he dropped the bomb. I have a 7 year old son that he was super close with. He claims that he needed to figure himself, that he is a sad, angry lonely man and I deserve happiness, that he needs space, that he is no longer attracted to our relationship(??). So he moved out, cried and hugged me...then as soon as his shit was out he was completely cold. He says we just "arent meant for eachother" and it is unlikey we will ever get back together, and that he doesnt care if I date or sleep(!!!) with someone else and to let him go. He deleted me and blocked me from his Facebook (which I still look at it). So On Easter I sent him a "goodbye take care in all your pursuits text" and he never responded...but then a few days later he texted me Happy Bday, then something about some concert tickets, then a few days later something about selling my car...well I have NOT responded and feel bad about it...i think about him constantly, even though I try very hard not to...I just keep thinking he will come back a changed man!!! I KNOW better, how am I giving myself this mindf*ck!!! I do not believe it is another woman, but maybe the freedom of looking if he wanted to. I struggle between wanting hoim to text me, and wanting him not too...I get super anxious when he texts and it continues through the night!!! I dont understand any of his actions...or what he is doing, if he misses me....it's just one huge mindf*ck!!!

-luvapug