On his OF he said he doesn't like labels. He wouldn't say he was bi, he said he liked men and women. While that sounds like the same thing, there is a nuance when people say not to label them.
Someone commented to the effect, maybe on Twitter, "Nice to see that Nick is gay," and he responded "I'm not. I've been with guys and girls." At a minimum, clearly he 'tolerates' a gay male jacking him off. He's comfortable enough with that situation to get erect and cum with him. But I have to wonder whether or not he truly desires other men -- in the least -- or he's just savvy and doing this because it's making him and his wife a handsome income.
If I were a betting man I'd say that he's 'mostly' straight and acting out for what he knows very well is his HUGELY gay audience. He can say "I've been with guys and girls" because, technically, it's true. But for my own personal, selfish fantasy, what I'd LOVE to know is the answer to that "bi" question -- whether he's ever voluntarily pursued another male because it turned him on, because he wanted to.