01/23/2012 08:30 pm ET Updated Jan 24, 2012

Heidi Klum, Seal Separate: 5 Other 'Alpha Wife' Couples

Heidi Klum and Seal confirmed late Sunday that they will separate after seven years of marriage. The news comes as a shock to friends and fans alike, as the couple always been considered one of the happiest in Hollywood.

But what went wrong in this seemingly-perfect relationship? Some have speculated that Seal's temper drove the pair apart, while others have said Klum's success -- the supermodel hosts "Project Runway" and recently joined the cast of "Fashion Star" -- might have something to do with the separation.

Research suggests that marriages in which a wife out-earns her husband are more likely to end in divorce -- perhaps because men feel emasculated, or women feel like their husbands are freeloading. News reports have even called this the "alpha wife" phenomenon, arguing that successful women are somehow destroying modern marriages -- though it wouldn't be noteworthy if the opposite were true.

But could this be true for Seal and Klum?

Seal's big hit, "Kiss From a Rose," was released in 1994. And though the singer is set to release a new album, "Soul 2," on Tuesday, Klum has remained in the limelight while Seal hasn't reached the same heights.

Below, five other "alpha wife" star couples who have called it quits.