A good read with a few flaws
There is a lot to like about this book and a few things to dislike. I liked the characterization of Rand, a deeply troubled man who feels the pressure to marry and produce an heir at the threatening behest of his autocratic, deeply oppressive, near maniacal grandfather.
When his chosen bride backs out, he chooses her twin sister, Helena. Helena is a good deal more reserved than her sister, but is determined to make her unusual bargain with Rand become a true marriage. I liked Helena's character but found her a bit to pliable and too ready to forgive Rand some of his contemptible behavior. Yes, Rand offers reasons for his behavior but in my opinion it happen more often than necessary.
There is a plot twist near the end that did surprise me a bit and seemed a little far-fetched. The final resolution to the gnarly situation facing Rand and Helena was a shade too convenient for my taste. Other than the few things I've mentioned this was a good book overall.
The novel does have a fairly high degree of sensuality in the sex scenes, but the author eschewed the anatomical, 'Tab A fits into Slot C' approach to describing them. Sex is initially the only way Rand and Helena can connect with one another and some of the scenes are beautifully written, if a bit too frequent.