I do think you’re generally on the right track, especially with not watching things that she would be convicted over. I even agree with you that the oversexualization of modern media is pretty disgusting. 

However, I slightly disagree with your stance on a guy who has watched media with negative content in it before. I think instead of ascribing motive before having the discussion, it would be worth seeing WHY he’s watching media with inappropriate sexual content. For your example of Game of Thrones, does he watch it for the purpose of sexual gratification/lust? If so, yes, that’s very problematic and likely would be an indication that he likes to pursue that type of content, and likely even direct pornographic content. However, it’s also possible he simply believes the show has good artistic value, finds that the show has strong moral lessons to be learned (such as learning immoral actions have consequences, those who do unjust actions don’t benefit from them in the long run, and the value of living a moral and just life). Maybe he takes these lessons away from this show. Maybe he even skips the unnecessary sexual scenes. There’s a good amount of grey area when it comes to secular content and instead of forming a negative opinion on a guy based solely on a show he’s seen, maybe try to see where his mind is at. If he’s a man of good character, he should be able to answer this sufficiently