The Silk Vendetta by Victoria Holt

The Silk Vendetta - The Silk House is home to the exquisite silk making family the Sallongers. Lenore Cleremont lives with her grandmother who designs dresses for the Sallonger family. Their rivals the St. Allengeres are in France and are a distant branch of the same family. Charles, Phillip, and Julia were children of the house. Drake, Charles university pal. She marries Philip, but he is killed shortly after their wedding. It is ruled a suicide and the stigma follows Lenore. Lenore and her mother escape to France and meet the St. Allengeres as well as the current Comte.