What is the theme in Waiting to Exhale by Terry McMillan?

Savannah, Bernadine, Robin, and Gloria are on quests for self-realization. Each believes at the outset that fulfillment is to be found in a lasting relationship with a man. The women cannot understand why they have been unable to achieve this goal. As they agree in a serious moment during a fun-filled party among themselves, they are "good catches." They are good-hearted and nice, youthful in manner, and attractive. Even overweight Gloria is "pretty." Yet "meeting Mr. Wonderful" eludes them all, a problem they see exacerbated by time.