This was a tough read, but not because of the hardcore BDSM - that actually worked fine for me. The tough part was Dylan's family, and in particular his brother Gary. The term "sadist" has both a specific meaning in BDSM (probably more than one - I am the farthest thing from an expert) and a more general meaning in everyday language, where it tends to describe a person who likes to make other people scared and unhappy.
Gary is both, but it is his desire and talent for making people miserable that warps his whole family and badly harms many others. A friend's therapist once told her that you could spot a person with a personality disorder thusly: everyone around them acts crazy and unhappy, but they cruise through life confident and serene. This is Gary to a T. You can fault the parents, but they would have done fine with Dylan and Carmine. And Carmine is a difficult and volatile character, but she has good reason to be (and the reason is Gary). Gary is handsome and charming and very good at gas lighting people - making them believe what he wants them to believe instead of the reality they should be able to look around and see. He is very confident that he will get away with his crimes, and with good reason - he has always gotten away with things. I suspect he would have gotten away with the rapes as well if(show spoiler)
didn't have the bravery and determination to make sure he didn't.
When Gary is arrested for raping several women in the context of BDSM scenes, Dylan (who goes by Dilly at this point) realizes he has to come to terms with his own fascination with BDSM, in his case on the submissive side of the equation. He goes to a bar called The Stonewall and there he meets the owner, Dolphinia, and Vin, who gives Dylan exactly what he wants and answers some questions for him as well.
One of the things I like best about Lyn Gala's books is how the main character finds a mate who is not even close to perfect, yet is very nearly perfect for that main character. Dylan and Vin are both kind of a mess. Dylan is passive, unambitious, not honest with his family, and not good at taking care of himself. Vin has the kind of history that marks him out as bad news -(show spoiler)
Neither is really a good candidate for a healthy relationship, but they are so well suited to each other that the relationship ends up being great for each of them and working very well. Each becomes more confident and happy, and less prone to use dysfunctional coping mechanisms.
There is a lot of discussion of BDSM customs in this book. Dolphinia and Vin (and, over time, Dylan) prefer a looser, more intuitive method where safe words may or may not be used and there isn't much kink negotiation or limit setting. This makes certain SSC fans incandescent with rage, and I get that - it could be very dangerous if the dom's intuition is wrong. But again, for these specific people it works and is healthy. Vin really can read what Dylan wants and needs from his expression and body language, and they don't need or want to talk everything over.
I Kindle-borrowed this book, because I was afraid I would not be able to get through it, both because of the hardcore BDSM and the awfulness that is Gary. But I think I will buy it and read it again, though I will probably skip the parts where Gary shows up. I didn't entirely "get" the BDSM, but I fully believed that the characters loved it, and I was happy for them to get it. This author's writing style, characterization, and dialog works really well for me, and everything I have read by her has been a pleasure.