It’s only a joke if both parties find the humour in it.
As it stands, your boyfriend is a jerk. My husband and I poke fun of each other a lot. We high five if one person gets in a particularly good burn. We also respect each other’s boundaries and there are topics that are to be left untouched. If I go too far and my husband tells me so (or vice versa), an apology is immediately forthcoming.
My husband and I can also be very abrasive and blunt towards each other. Like all humans, we both get days where we’re feeling extra sensitive, even if it’s irrational. On those days, the other person acknowledges it and moves on. There’s no “You’re being sensitive, blah blah blah”. It’s called respecting your partner, which your boyfriend isn’t doing.
You don’t want to be with someone who sees his partner as the problem and pushes the responsibility of solving the “problem” onto you so he doesn’t have to do a thing.
I really hate the ‘You’re too sensitive” phrase. What it’s really saying is “You’re calling me on my bad/rude/disgusting/hurtful behavior, but I don’t want to change or deal with how much of an asshole I am, so I’m going to deflect this and blame you.”
Grabbing your stomach and squeezing? No, just no, full stop. That is not someone that cares about you or respects you.
Keep rethinking.
What you’ve described here isn’t you being sensitive. It’s him being an asshole.
You’re with a textbook emotional/verbal abuser and I urge you to leave NOW before you feel stuck
You’re not too sensitive. You don’t want your boyfriend to say mean things to you, that’s pretty fricking normal to me. Also the stuff he says about his family, huge red flag. It means that this shitty behavior is something he’s learned from his parents, he considers it normal and he has no intention of changing it.
What’s the point of having a boyfriend if he’s mean to you? Shouldn’t he tell you how great you are and how much he likes you?