This is that rare m/f romance where the Him-Dominant/Her-Submissive relationship doesn't clash with my feminism.
It is clearly a bedroom-only power exchange without the ritual and role-play. Erin is a strong, tough woman who knows what she likes, and she likes to get her freak on.
The story is good too. Erin and Todd reunite years after a brief relationship, they become a couple, and gradually Todd's best friend Ben joins them and they establish a threesome. Meanwhile Erin is dealing with panic attacks and grief and all the fallout from a few years earlier when a stalker attacked her and killed her child.
If you've never read Lauren Dane, this is a good one to start with.