Classroom Dilemma

Hi, my name is Mae and I'm fourteen. My ex-boyfriend (Mark) and I went out for seven months but we didn't kiss. Is that strange? We broke up in November because we barely talked anymore and now I miss him but he doesn't look like he misses me that much. We're in the same classes so I see him nearly all day at school. There's this other girl, Ruby, who he's always messing around with and he's written "I <3 Mark" on all her stuff. I keep telling myself that it's just to annoy her because she always says that there is NO WAY she likes him, but do you think he might like her? Please help, I'm really confused.