I agree with Sagittarius84.
I really wonder if a man who had never been aware of or acknowledged in any way, any sexual attraction to another man, i.e. 100% straight, would find being deprived of sex with women so hard (no pun intended) that he would switch to having sex with other men. If other men were all that was available I suspect he would simply masturbate to private fantasies of women rather than engage with the men around him.
But that doesn't mean there aren't plenty of men who are living straight lives who would do something with other men if that is all that is available. But these will be men who are aware of at least some level of sexual attraction to other men, even if it is weak compared to their attraction to women.
So it's much the same as the question that has been asked before about men seeming to become more bisexual, i.e. less straight, more prepared to have some fun with other men, as they get older. I think the attraction was always there but it wasn't dominant and expressing the attraction for women, and suppressing the attraction to men was the course of least resistance when younger.
I also don't think there is anything dishonest about this - in monogamy, your partner at any given time can only be either a woman or man.