Their Own Desire.

Lally is a rich girl whose father writes books and plays polo. After 23 years of marriage her father decides to divorce Lally's mother and remarry to soon-to-be-divorced Beth Cheever. This sours Lally on all men. While on vacation with her mother she meets Jack, who succeeds in stealing her heart. Then Lally discovers that Jack is the son of Beth Cheever, the woman who is to marry her father.