Same thing happened to a guy in South Florida who was a MS and married with 3 kids and a regular pioneer for 20 years.
She wanted to go to a company party, he refused, she went any ways, stayed over night and home the next day to declare to him that she was a lesbian. She was willing to stay with him till their 16 year old daughter was ought, and give him the marital due, but her deal included time with her new found lover.
He said no deal!
The hardest thing he told me was; "I can compete with another man, but how do you compete with another woman?"