It seems like you know what you need to do. Politely ask him to stop cursing when you are around. Say something like, “I really like you, but I hate cursing. Please don’t do it when I’m around.” If he likes you, and respects you, he will stop. It is likely that this is a habit for him, however, so it may take some time for him to stop using those words on a regular basis. As long as he makes an effort, things will change, and you’ll better be able to enjoy a relationship of some sort with him. But if he doesn’t stop cursing when you are around, stay away from him. By ignoring your request, he is showing that he’s not interested in you and doesn’t respect your needs and wants.
Best of luck!