Why do I fantasize about being overpowered by my husband?

I genuinely don’t know what to think. He’s a very kind man and he was raised to treat women with respect. He’s usually the one who initiates intercourse (I was raised rather conservative and sex wasn’t something we really talked about). But I have this really deep fantasy about him just overpowering me and having his way. I don’t know why but it’s something I want him to do so badly. Help? Why do I have this fantasy??