My fiance finds a way to talk about an ex everyday?

[Southern girl]

My fiance keeps telling me how he wants to get married, etc. Etc. I'm just very worried because literally every day he finds a way to bring an ex up. I've never dealt with anyone doing this before so I don't know what to make of it. He brings them up in general comments on his own, makes jokes about them... makes jokes about a couple of them saying he wants to get back with them... really, everyday he says something about an ex and I tell him it isn't funny & no girl cares to hear about his exes... the past is the past as far as I see it... I know I don't bring mine up or go out of my way to talk about mine... when I say something to him, he says he's "kidding"... this is stuff that's obviously not even funny at all. I'm wondering if there's anything behind it or what is the reason he does it for?
I give no reaction to it... until tonite when I thought he should really just know how embarrassing it is because he says things loudly in public.=\ then he's all over me directly after saying how much he loves me...(barf).... I mean really??? Its kinda like two or 3 exes... the one b4 me, he does this most with, then sometimes the other two... he will have mean things to say, snide "jokes" which arent even funny except to him... and this one who he's like "Omg her family is so rich, has the nicest house, their own plane, yatta yatta yatta"... they dated in the tenth grade for Goodness sake! Does that even count?!
.... he's now 25 years old. Just to clear that up.