According to Betty Fusell's Mable: Hollywood's First-I-Don't-Care-Girl... Mabel's lifestyle was taking a toll on her health and well being. Being diagnosed with TB, her condition was not in good favor, when she began having an Affair and relationship with Studio Owner, Samuel Goldwyn.
It was also written that she became pregnant, and lost it due to a miscarriage. Though they did not marry, the both of them remained good friends.