I never used to swear. When I was little, we didn't DREAM of swearing, and "Shut Up" was the worst word we'd dare to use, of my mom would spank is, hard. Even if she caught us telling someone to shut up.
Over the years, I've gotten less anal about it, but I don't swear like a sailor (btw...that is a true saying...I know quite a few sailors now and good god, lol!) I do let "dammit" and the occasional F-bomb drop, but I've curbed my language around Nina. If she eventually hears a bad word and asks about it, I'll tell her that that's an impolite word that we try not to use.
There WAS a moment last week, though, I dropped something out of the fridge, and winged my head, really hard, on the freezer door while standing back up, and let loose a loud, "Holy frick on a goddamned stick!" right in front of Nina! She looked at me all wide eyed, her thunder-brows of thought/focus going full force, and then smiled and went back to romping around when she established that mommy wasn't mad at her, lol...
When she's asleep, or we're with friends, I admit, my language gets a little more free and foul...all of ours, do. We always joke around and tease each other, especially when gaming, but if Nina's out and around us, we tone it down.