For Regency/Georgian romances, Georgette Heyer is the best.
There is no sex in her books, but frankly, her grasp of language, historical time period, culture and character would make it unnecessary padding. She builds up romantic/sexual tension with words so that by the end of the book a single kiss is more satisfying than 16 pages of explicit sex.
Try "These Old Shades", "Frederica", or "The Grand Sophy".