There's enough science to corroborate that sexual behaviour does not necessarily reflect the person's true sexuality due to social norms and conformative pressure. In societies where sexuality is strictly controlled and narrowly specified, deviates are strictly punished either socially or by the law, or both, in quite a few countries even with death penalty. We don't need to go searching for societies where (heterosexual) marriage is inescapable, no matter what your true orientation was, they are so plenty.

Likewise: many gay porn actors are actually straight for the simple reason that they earn more "becoming gay". You cannot tell their true sexual orientation observing their sexual behaviour.