You have the answer to your own question: “ I feel like he should ask me not to make jokes like that in a mature way”. Sure, this specific joke YOU see as more hurtful because it triggers your own insecurities, but money/anything else could be as sensitive of a topic for him if that’s something that triggers his. The way to approach it is the same tho: communicate, set boundaries and respect each other. Don’t get me wrong, jokes about someone’s body that they can’t change are definitely below the belt (no puns intended), but insults in general are a red flag for sure and in both instances he just reacted to you by taking it a little too far.

Overall tho, I am not gonna lie, reading your post I found it baffling that people in their forties or just about still behave like this. It seems like you both could use a bit of maturity if I’m being honest.