Guys 13-15 any advice? what do you think?

ok so theres this guy i went out with in febuary, hes the type of guy who cares what everyone thinkks so after 2 days of going out hebrokeup with mee. like a month or 2 after we brokeuphe told me he still liked me, he stilll likes me niow like even my gfriend tells me he tries to bring me up and taslk about mee in the classes she has with him. i'll see him looking at me sometimess but i dont see him tht often in the hallway. anyway,sinnce i said before he cares so much about his rep, to atc cool , he'll trash talk about me to his friends.. basically jstt say im a slut..so any adivce> does he like me? why is he doing this>? thanks.