AIO or is this a little weird

Basically, me and my bf have been dating for half a year now. He has exes and he still keeps in contact with them but I don't really understand why. One of them has literally cheated on him but they still would talk on Snapchat about stuff. They haven't talked for about 3 months and he says he's getting rid of snap but I still find it a little weird? I mean he basically just says he never blocks anyone even exes but I just don't understand being friends and talking with someone who cheated on you. His other ex doesn't really talk to him but her friends reach out trying to get info on me and he'll text back. I personally just don't talk to any of mine but maybe that's just me. He also still follows them on insta, even their silly spam accounts.Idk I think it's just weird but he stopped a while ago and he doesn't lie about it or anything. Am I just being dramatic?