This plot seems more like a simple power fantasy with the MC saving the day and getting all the pretty girls. But there's an idea here that could lead to erotic horror. I mean all the men have turned into zombies but the women appear to be fine except they are really horny, then you could introduce a male rescurer who has sex with one of the women and then he becomes a zombie. This causes the women to realise they are carriers for the zombie plague which could lead to fear, paranora, sexual frustation and the thought of should they even get rescued