The main problem I had with this book was not the fact the protagonist was unlikeable, although he is. Pyke is shown as, not just described as, hard, cruel, vicious. We're shown that he treats people (women) appallingly on more than one occasion. That's fine, that's not necessarily a bad thing in a protagonist.
The problem is the inconsistencies. One moment, it's clear that he and the author knows that he's not likeable, that he's meant to be an antihero. The next, his actions are excused or overlooked. He always manages to trump people in dialogue, insulting and outdebating them and getting away with it. In the first few pages, it's made clear that he's attractive "though not in the suave, if effete, manner of an English gentleman". No, Pyke has to be masculine, and (also made clear in the first few pages) has no trouble getting women and that he dumps them, they don't dump him.
He does something that is nasty, and while it's being done, it's presented as him being a hard man, borderline criminal, ruthless. After, though, there's an explanation, like him explaining why he had to do it, one that she (and we) are meant to accept. It's like the writer wants to show his hardened credentials, look at how tough, how nasty, brutal this guy is, but doesn't want to give up anything for it-- he's still attractive, intelligent, better read than a lot of nobles, cleverer, his actions are forgiveable in the context of his life. One moment, we're told that something he's done was pure pragmatism, unapologetic. The next, there's the explanation, the reason why his actions are acceptable.
The writing style is distant, I think in part to make it feel more appropriate to the era. Everything feels described, rather than shown.
In short, not a terrible book, but not one that does anything for me or that I'd particularly recommend.