Communicating frustration

My boyfriend and I had very different upbringings.

In my household, when someone gets annoyed or irritated by someone else we yell at them, call them an idiot, “leave me alone, stupid” and so on. We know that we don’t mean any harm, it’s just the way we talk.

However in his household, emotions are withheld, all emotions, except the occasional laugh of course. So now that we’re living together and he does something that bothers me (let’s say he left the toothpaste open and his towel on the ground), I’ll go to say “why would you leave this here, and you’re supposed to close the toothpaste after you use it dummy” (mind you he’d have to do this a couple days in a row, if he’s in a rush for work or something it’s whatever), but then I stop myself because I know he’ll be like “I never yell at you, don’t call me that!” And he’ll take It really personal even though I don’t mean it, it’s just how I grew up!

Not that I’ve been holding back for the past few months, I feel like there’s a lot of pent up anger that I never got to release and idk how to do it. A 2 second meaningless sentence makes such a big deal to him, but I have no idea how I’d take those tiny frustrations out otherwise. What am I supposed to do, break some glass, inhale exhale? Is this normal?