I can't believe how sheltered some people are.
It's not totally unheard of, especially in the acting industry.
Vanessa Redgrave's father, Michael Redgrave married, had children, and also had same sex lovers.
I think Joan Plowright admitted that her husband, Laurence Olivier, was know to have had gay lovers. I think his son, Tarquin Oliver may have talked about it in interviews about his dad.
Alan Bates is also another good example. Wife; Children; liked 'male company'.
Julia Blackburn wrote a book (The Three of Us) about her bohemian parents and how her dad, the poet Thomas Blackburn, was having a love affair with the painter, Francis Bacon.
Philip Schofield. Huw Edwards. Two recent ones... Huw Edwards has 5 children but has a thing for young men. Must have been awkward for his daughter's boyfriends...