Why do men text their ex-girlfriends?

My ex-boyfriend has been texting me pretty regularly for almost 2 years. (He’s been married for 5 years). He hasn’t asked to meet me but tells me when he comes to my city. (Once he texted me that he was going to a concert in my town and asked if I was going, too—I said no). All our texts have been on the up and up and neither one of us has indicated we have any romantic / sexual interest in each other (though we both have legal backgrounds so we’ve always chosen our words carefully). I miss him in a less than platonic way so I’ve considered asking him to stop texting me. But, I don’t want to embaress myself if it turns out I’m just one of his text-buddies. He indicated he doesn’t respect his friends who cheat on their wives. But, if I were his wife, I would consider him texting an ex a form of cheating much less when he sometimes spending hours doing it. It’s unlikely anything could ever come of us texting, Just the same, I’m putting this out in the universe because I don’t have anyone I can talk to about this. So, why do men text their exes?