What Is Romance, How Does It Work

I'm interested in learning how to write better smutty romance, so recently I've been reading a lot of popular "guilty pleasure" novels and fanfic. I've noticed that a strong thematic undercurrent running through all of these narratives is the difference in power between the two parties. Although the conflicts that arise because of this imbalance are always resolved by the end of the story, it seems to be very important that one partner is repeatedly placed in a vulnerable and imperiled position at the hands of the other. If the two protagonists are of opposite genders, the woman will be physically and verbally threatened by the man. If it's a pairing between two men, the violence that the more dominant partner enacts is even more concrete and pronounced.

I'd really like to know where the appeal lies in all of this assault. I don't mean to kinkshame anyone - quite the opposite, in fact. I feel almost as if everyone is in on some secret that I haven't been told yet, and I very much want to be inducted into the inner mysteries of literary sexytimes.