I was on Boston common today, talking to a friend. We’d just gotten to know each other and we were asking the kinds of questions people ask, exploring each other’s lives. He asked me, “Since you’re gay, how did you manage to stay married so long? How did you do that?” 
I told him, “Even though you’re straight, you could do that too, have sex with a man,if you wanted to bad enough, or if you needed to, or felt you had to.”
He said, “Not if my life depended on it.”
I laughed. “That’s probably the wrong kind of stimulus to be brought to bear on this issue. But something else. Look, people do it all the time. They don’t change their orientation. You can’t do that. What they do is go outside their orientation for a short time. I did it.”
“No. Nothing can make me able to have sex with a man.”
Probably each person requires a different kind of stimulus, but people are subject to external stimuli.  Money is a stimulus for some people. Give them enough, and they’ll do anything. Other people, something else—respect, place in the community, power. There is a whole range of things that affect how men and women choose the gender of the person they are going to have sex with, and getting turned on is only one of them. Witness the millions of gay men who have gotten married and fathered children in the last hundred years. And the probably smaller number of straight men over the years who have had sex with gay men under a range of stimuli—often alcohol or drugs. We discussed the opening scene of True Romance and Christian Slater’s character telling us under what conditions he would have sex with Elvis Presley. If I had to. I mean had to. He thought Elvis was as pretty as any woman.
What I didn’t say to my friend, but could have, since it is true, is that sexuality is malleable—to an extent and for a short time. I could also have said that a man can’t permanently alter his sexuality. But anybody can do anything tonight, if the stimulus is right.