He just wrote "I love you" on his ex's wall....what is going on here?

So my long distance bf just wrote "Love ya bestie" on his ex's facebook wall. What the heck? Like he doesn't think I can read. Or thinks that it severly hurts me? I won't say a word about it because I don't want to argue, but I tell my ex all about whats been going down. But he still loves me and I don't want to hurt him by mopeing over this guy to him. I just want to be cared about in a relationship, not pull all this weight. What the heck is going on?