Why is my ex saying such mean stuff?

Hey guys =) I dated this guy (Tristan) for about 7 months (i know its not THAT long), and he told me he loved me..etc. I was finishing up my spring semester and I decided to go to italy and spend the summer with my mom (she lives there). I told tristan and he was okay with it and we decided while i was gone for the summer we would still be together. When my departure date got closer, he started acting funny and I knew something was up. (as a little backround, I really dont get along with his best friend because he tried making out with me when I was dating tristan, yet TRIstan didnt care and still hangs out with him…I WAS SO MAD!)..anyways…he told me the day before I left that he wanted to be single. he cried alot (i did too), and he explained how he loved me so much and he really didnt want to hurt me, after an hour of that he left and then he called me a bunch of times the next day and i didnt answer. I left for italy and now im about to return home in 20 days (yay!) and i have heard from a ton of people (my friends, his friends), that he is talking SHT about me!! He is calling me a btch and a psycho, and saying he never wants to see me again and he hates me. Now, the last time i checked he BROKE up with ME! He tried to get into contact with me when i was italy (he even called my dad!) but i just ignored him. I mean, i have nothing against him, i just dont appreciate him talking sh*t about me! I really dont respect him for that, and I dont want to see him when i go home. Now, my question is..why is he saying all this mean stuff, when i never did anything to him, i am a genuinely nice person, and i dont think he had the right to say anything like that. I mean, if i’m wrong, please tell me! thanks =)