Re: historical romances
Sharon Kay Penman, although they are not romances .... it is more or less historical fiction based on facts.
Margaret George is another great author. She wrote the Memoirs of Cleopatra, a massive book, over 1000 pages, but I greedily read it just under a week. It was so well written.
Sharon Kay Penman incorporates romance into her books. They are excellent!
If you want to read about a great love/hate relationship, read about Eleanor of Aquitaine's marriage with King Henry. Volatile and dramatic stuff. One book based on their romance is Time and Chance. The sequel is yet to come out.
Any of her books that deal with the Plantagenets are good. You will get your dose of romance, drama, history, etc. all in one go.