I believe he cheated on her as well.
People with that massive ego usually do.
I seen to recall from reading several Patton biographies that he had an ongoing affair with his wife’s niece (can’t recall the niece’s name off the top of my head right now). As one might well imagine, this was quite explosive within his family (his wife, two daughters and one son). Although his flamboyant style of command was what was called for at that point in time, it proved to be his undoing in many instances.