My boyfriend always says "f*** you" or "f*** off" to me?

He says it in a joking manner, but it still bothers me. He has never said it out of anger or to intentionally hurt me. I've told him before that it bothers me when he says it, but he says it just slips out because that's the way he talks with his friends and roommates. He apologized and said he wouldn't say those things to me anymore, but I still find him saying it a lot. Am I being unreasonable by being upset about this? Even though I know he's just messing around, I still feel like he shouldn't be talking to me like that.