Porn can stimulate the fantasy part of ones brain.
Someone posted a thread asking if jacking off was gay . I think I answered, that if one is thinking of a woman taking the place of your hand, then it is hetero. If one is thinking of a guy, replacing your hand then the fantasy part of your brain may be a little Bi or Gay.
Same for watching M F Porn. If you watch and envision yourself as the guy getting oral or penetrating the female, that is one thing. However if you watch M F Porn and you envision yourself as the woman, giving the male oral; or being penetrated, Wellllll that may just be a little Bi
Then again some guys look at the M and F in the video and fantasize about getting oral / topping them both. No harm no foul. But fantasy is just fantasy, until one makes fiction fact
Just my opinion