Elyot remarks to Sibyl that, "Apart from loving me and all that, you must have plans." What does he mean by that and why would he accuse Sibyl of it?

Elyot says this in response to Sibyl's declaration about what is suitable for a man and what is suitable for a woman. He believes that Sibyl wants to change him into the masculine archetype (ironically typified by Victor) of a rugged, gentlemanly protector. From how he states his case, he is convinced that Sibyl, despite her innocence, has a natural craftiness granted to women that will gradually manipulate him into being someone he is not in order to satisfy what she believes a man and woman should be.