Conversation so far:
How many times was Ethel Merman married?
Merman was married and divorced four times.
Who did Ethel Merman marry first?
Her first marriage, in 1940, was to theatrical agent William Smith.
When did Ethel Merman divorce William Smith?
They were divorced in 1941.
When did Ethel Merman after William Smith next marry?
Later that same year, Merman married newspaper executive Robert Levitt.
What happened with Ethel Merman's marriage to Robert Levitt?
Merman and Levitt were divorced in 1952.
When was the next Ethel Merman marriage after Robert Levitt?
In March 1953, Merman married Robert Six, the president of Continental Airlines.
What happened to Ethel Merman's marriage to Robert Six?
They separated in December 1959 and were divorced in 1960.
Did Ethel Merman re-marry after divorcing Robert Six?
Merman's fourth and final marriage was to actor Ernest Borgnine. They were married in Beverly Hills on June 27, 1964.
Did Ethel Merman and Ernest Borgnine stay together?
They separated on August 7, and Borgnine filed for divorce on October 21.

Question: Why did they split?
Self-contained rewrite: Why did Ethel Merman and Ernest Borgnine split?