I think you do need to change something. Adults do change their minds if they think things over and realize they made a mistake, right? (I do it frequently myself).
So rather than compromise yourself, or put yourself into the false position of moral arbiter so he can bleat out, “You said I could watch this” as he watches stuff that makes you–the owner of the TV–uncomfortable–
I think you should listen to the advice you have.
Sit him down and say, “BFF, here’s the deal. My house, my rules. As a adult, I have chosen the type of programming that I watch in my house. As a guest, you have the obligation to follow my rules in my house. So, if you want to watch something that I do not care to watch–for WHATEVER reason–either you accept my decision, or you go somewhere else to watch it. Because I have the right to watch what I choose and not to have to watch something I don’t want to because somebody else wants it.”
And don’t back down or be cowed. You’re an adult, he’s an adult. If he is entitled to ‘watch what he wants’ SO ARE YOU. You’re not his entertainment center. Your TV is not his TV. It’s not in the public domain.
Don’t let him try to argue that you’re being ‘unfair’. You’re not. Don’t let him sulk or try to compromise. Give an inch, he’ll take a yard. Believe me, I know.
If he doesn’t respect you over watching a TV SHOW. . .he doesn’t really respect YOU as a PERSON, even if he thinks he does. Even if you want to think he does.
So give him the straight talk and let him think about it. After all, he can always change too. . .right?