Relationship

Need help...I'm in high school and broke up with my ex over a year ago. Since then I've been in 3 short relationships that honestly failed. I've been thinking about him a lot today but haven't texted him or talked to him at all. I unfortunately attended his grandfathers funeral today where we hugged and spoke for the first time since the break up. Before we broke up we had been together for a year and been friends for a year previous to that. The only thing is that while we were together he cheated on me with our best friend. But since then I feel he has grown up a lot but sure. I think I miss him but don't know how to be sure or if it's just the emotions from the funeral and everything else. I'm not sure if he even misses me at all. I basically don't know what to do...Any advice???