This is my first Ainsley Booth novel, so I don't know if this is her usual narrative style or something she was experimenting with for Shame, but the narrative was simply too sketchy for me to feel any attachment to the protagonists or any angst about the infidelity that tore apart their marriage.
As an example, we learn early on that the OW he has been cheating with for three (?) years was an outside counsel the husband hired to help straighten out the legal mess his investment firm was in after [something to do with his brother's gambling addiction, which I assume was explored in the first book in this series]. Later we're given a flashback to the husband and wife having an argument in bed about how he's treating his brother and about their sex life, then "in the morning I go into the office to meet two lawyers from a new law firm we're considering hiring as outside counsel." Great, clever, subtle, but...that's where the narrative thread ends. There are choices and actions that lead to the start of an affair, but we're not going to see any of those, just the fragility of the marriage that allowed the cheating to happen and the opportunity that walked into his office.
This is particularly unsatisfying considering that the story is narrated from a dual point of view, and the cheater never reflects on the cheating. Even in therapy, his motivation isn't clearly examined. Which is a pity, because one of the best things about the story is the indication of his feeling emasculated by the collapse of his business and his wife stepping up her career as a commercial artist (of erotic sculpture) to stabilize their finances. I imagine the affair as an ego boost and a way to punish her for succeeding when he felt like a failure, but I'll have to be satisfied with just imagining it, because Booth is not going to pin that motivation down.
Although I like how kink was used as a device to illustrate the lack of real intimacy in the marriage, to heighten the betrayal of the infidelity (he wouldn't indulge his wife's desire for kink, but went there with the OW), and to provide a path for re-establishing their bond, I also have to admit that kink doesn't resonate with me and only served to distance me further from the characters, particularly the heroine, who seems to be setting a trap-filled path for the more ignorant hero when she says, "I'm going to say some stuff that makes me sound young, but that's a variable headspace state for me. It comes and it goes, and I'm always Grace....I love our size difference, so if you call me little, I love that, and i like being baby girl, but I don't like any specific references to me being a child or anything like that." So she wants to do Daddy play, but if he does anything to indicate that he sees her as a child, she's going to get creeped out. That feels like a really fine line for a newbie to dance.
Three stars because I can't justify lower or higher. To do either, I would have to decide whether I think this is romance or some other form of fiction and I can't go there right now.