Can't believe this

So here's the story, I had an apartment with my ex boyfriend. Mind you he put me in jail for slapping him, he went and got an injunction against me while I was in jail. Our hearing for it was last Friday, he decided to drop the injunction. Saturday he messages me on Facebook tell me how much he loves me and wishes things were better, etc etc. I was stupid enough to fall for it and messaged him back, he wanted to see me that day after I got all the stuff out of our apartment. Come to find out this whole time he's been messing with his sisters best friend, even had her stay the night in my apartment. Then today he emails me saying "I never wanted you or her I've been talking to someone for the longest time and I'm happy with them, I wanted things to turn out the way they did". I just don't understand how someone can be so heartless towards another human being that took care of you while you weren't working.