H.M.
Well you are half right in my opinion. I agree he should not use foul language towards you. But if he is saying this in any other manner what is the big deal really. They are just words. A form of expression. I would tell him nicely if he is just using them in manner that you don't like it. But i sure as heck wouldn't say to him that if you choose to use these words go live with your dad. Idle threats are pointless. Not to mention you are telling him that something as insignificant as swearing will exclude him from your house. That you don't really want him all that much. I mean that has to hurt pretty bad. If you tell him that using those words you don't like and he shouldn't use them in your house is fine. It will take time to reprogram to not use these words. I mean no one wants to be nagged night in day so he will start to taper off on using them. Now if he is calling you names that is a whole other story...I would be much firmer with that.
You know I am only 25 and I didn't swear at my mom or ever in her prescence. But I had siblings who did. Mom did just this and you know what it worked, well for that matter. Mind you when mom wasn't around they swore like sailors. LOL!