So many people were surprised when Al and Tipper Gore divorced after 40 years of a seemingly ideal marriage. But recent evidence indicates that this is a growing trend.

Divorce lawyers interviewed by The New York Times said that one of the fastest growing segments of their clientele is the middle-aged and elderly. And it isn’t just a bunch of older men trading in their wives for younger ones. Rather, an AARP study found that women initiate later-in-life divorces more often than men. Most of these women found new partners if they wished.

Both men and women who divorce later in life do so for specific reasons, not impulsively. One big reason: it seems that no matter how accomplished they may be financially and/or socially, they find themselves stuck in an unfulfilling rut.

Typically, older women say that they have grown tired of caring for others while ignoring their own needs, and older men say that they tired of working to support spouses and children whom they feel don’t appreciate them. And with increased life expectancies, both groups see fewer reasons to stay in their unhappy marriages.