Yes, considering that coming out of the closet, some people can stop talking to you, your family can turn against you, the work can become a hostile ambiance, you may be forbidden to go to the church, be scolded when you to to school/college, be harassed simply when walking in the street....

How can someone be so coward to care about those trifles?
Such a cowardice!

Reading your description, the problem is not exactly that your friend is homosexual, but that she feels attraction for people other than her husband.

They are women. But they could be men. The problem is not really her sexuality, but fidelity.
Do you really think his husband would accept and understand something as: "I feel needs you can't satisfy, and I need to cheat on you"?

Cheating her husband may not be right, but honestly, it's a problem between her and her husband, and I don't think you have anything to do it.
Neither have I that, although I don't even know her, I'm aware of her private life.