Divorce for those older than age 50 has increased markedly in the last two decades. People often express surprise when a couple married for 20 or 30 years head for divorce court. It really should not be so shocking, as the societal sanctions for divorce have fallen, fewer individuals are willing to "endure" a bad, sterile or empty marriage simply to keep up appearances.
But across that spectrum, there is also a wide spectrum of options available that range from divorce to something less than that. Why you might want to avoid a traditional divorce, is money.