It's always kind of funny to me when an FL doesn't see how telling her fiancee "btw if you wanna cheat on me and get divorced that's okay" would come across, especially when her fiancee doesn't have feelings for anybody else. It's a pretty common thing in isekai stories, and while I get the logic in it, it never ever pans out.
Well, I like the jealousy moments it brings though, so I don't mind it :3