How do those married-for-decades couples beat the odds? The Wall Street Journal talked to several couples who’ve spent their lives together, among them rock star Ozzy Osbourne and his wife/manager Sharon, former President Jimmy Carter and former First Lady Rosalyn, and professional gambler Doyle Brunson and wife Louise. The Carters say it’s important to keep separate work lives. Sharon Osbourne said it helped to be stubborn, sticking it out during the tough times—for the Osbournes, that was drug addiction. The Brunsons agree; they were tied up and robbed at gunpoint. Jackie and Ken Egan have relied on laughter over their four decades of wedded bliss. "You need to learn to find the humor in each other's annoying habits. It helps you keep the affection," says Ms. Egan, 69.