SOLVED. Romance book where hero is rich and heroine poor and they get separated because hero's dad blackmails heroine to reveal her secret

[Bookworm]

Heroine is a singer and performing in a resort when the owner arrives and heroine realizes that it is hero the love of her life. Then it is revealed that hero has already married and has a son and daughter. The heroine has some throat problem but even after doctor forvade to sing she continue to sing. The hero sees that heroine is unable to sing mid performance the hero saves her and the doctor tells her to take some days off as vacation. The hero still thinks of the heroine as a gold digger so he offers her to be his mistress. The heroine also meets heros son in the restaurant and there the boy creates a son. After becoming hero's mistress the heroine improves the relationship between the hero and his children.

[Bookworm]

I found it finally. It is The Devil's Price by Carole Mortimer