Oppenheim, E. Phillips: Anna the Adventuress v1 22 dec 2008
Another one by "The Prince of Storytellers":
Anna and Annabel are twin sisters. Anna is the shy art-student, Annabel the famous parisian dancer. Annabel's husband disappears after an accident on their honeymoon. She believes him dead, poses as her sister, flirts with her sister's boy-friend and marries a wealthy magnate. Her husband reappears, of course...
There was even a (rather unsuccessful) movie by the same name.
PS: Please do not jump directly to chapter One, I included two alternative covers
PPS: The man is spelled Phillips. I will correct the other posts accordingly.