I really enjoyed this book, which surprised me, since I don't usually read novels that take place in medieval times, preferring the 17th-19th centuries. But this story was really good, one of those arranged marriages, resented by both parties, that turns to passionate love, but without going overboard with the usual scenes. There's drama, but it never becomes melodrama. They argue, have misunderstandings, and separate for a time, but it's never overdone. (In fact, while they're separated, Serena and Giles keep in touch through letters, though they keep their true feelings guarded. Serena doesn't tell him that she's pregnant, but only because she thought he went back to his former mistress.)
Serena's the kind of h I like. She's nonconformist, but undefiant about it, she's strong and independent, but also sweet and feminine, she has athletic skills and rides a horse like the wind, but also grows herbs and tends the sick. She was furious at her father for arranging her marriage, on the instigation of her selfish stepmother and declared she no longer considered him her father, but later regretted her words and asked his forgiveness. And every time there's a problem between her and Giles, she never lets her anger get overboard and tries to work things out.
Most of their troubles stem from Giles not being able to trust women, because a woman he once loved, and who gave him a son, married a wealthy, titled man, had no interest in their baby (even tried to abort it) and told Giles she never thought him good enough, being a bastard son. His illegitimacy made him feel insecure and less worthy, and he actually resented his mother for not aborting him, that's how troubled he was. He brought all this into his relationship with Serena, preventing him from consummating their marriage for a while, leaving him jealous of any attention she got from other men.
Serena grows to care for Giles's little son, Alan, and he thinks of her as a mother. She wants children of her own, but there again, Giles lets his feelings get in the way. A pregnant woman Serena tried to help suffered terribly and then died, and Giles was afraid the same thing might happen to Serena, so he used a messy form of birth control, that makes you wish tissues had been around back then!
These and other incidents at court, like Serena attracting the attention of the lecherous Prince William and his gentlemanly brother, Prince Henry, and her sneaking into a tournament to show off her skills to Giles, (not to mention Serena's jealousy of the women in Giles's past) cause more troubles but keep things entertaining.
There were two things I really appreciated, considering the book was written around 1980. One was that Serena wasn't raped, and that includes by Giles, who never forced himself on her; things could get a bit rough but never go too far. Also, a brutal rape attempt was stopped in time, before Serena was harmed.
The other thing was no infidelity, except for one regrettable time that Giles slept with Alan's mother, more out of anger than passion, and he regretted it terribly and admitted it to Serena, who later on forgave him. Other than that, he resisted the many advances of his former mistress, Bede, while Serena made it clear to the hopeful Prince Henry that she valued his friendship, but that was as far as it went.
There's more to this story, but I don't want to give anymore away, and will just recommend that you read it.