Son Says Words

My son says a lot of potty/vulgar words. I find myself getting so angry and frustrated with him, though it happens time and time again. Here’s my unintentional model. I need some help on where to go from here, please.

C-Son says words
T-He should know better
A-Yell at him/send him to his room/feel my blood pressure rise/get a headache/keep spinning in my head about him not knowing he shouldn’t say those words because I’ve reprimanded him before for it
R-I should know better than to think he won’t say those words