Wild and unrestrained, you are probably quite right. But while subdued? And if the chimp has been raised in captivity with humans, would she be as prone to object? I’ve seen humans and great apes in very intimate (though not sexual, of course) contact, and nobody was getting dismembered.
Of course, there’s no way to know for sure, it would seem. But given the prevalence of human perversion, coupled with centuries of ape captivity in circuses, zoos, for scientific research, etc., I think it’s quite likely humans have copulated with apes, perhaps hundreds or even thousands of times throught history.