Feeling down

Why does it have to hurt so bad after a break up? :-( I just feel so sad n alone.. why is it easier for a guy to get over it than a girl.. I left on thursday n he hasnt even called..texted to say sorry nothing. Ive gone to his house to pack up more of my things n I dnt say anything to him but he just sits in living room like this is no big deal.. like he could care less. We were together 3 yrs n I dnt know y im hurting so much hes a very verbally n mentally abusive n at times physically abusive so I got fed up n left but I just feel sad n cry all the time n I wish I could just let go n move pass this. :-(