I’ll give it you – this falls under the deeply awkward to profoundly troubling category. That said, if we are all to be judged solely on what porn we’ve ever watched, this country would grind to a halt and nobody would ever make eye contact again. My eyes, like many others, have seen the glory of some hideous porn.
But your situation strikes me a bit because you found bestiality porn on his phone. Like, not even his laptop. That means he had a mobile yearning for animal f*cking porn. Heavy. Is it illegal? I think so. It must be. It’s abusive to animals. How is hitting a pony different than coercing a German Shepard to hit you up from the back? And though the saying let sleeping dogs lie, has its place, I think this whole situation deserves some dialogue between you two. Do you really want to be long term dating or marrying a dude without vetting this to some degree? Not that you are fearful he will leave you for a Jersey heifer one day, but masturbating to animal sex is curious business. Bring up the topic. Don’t treat him like a vile miscreant off the bat, but engage him as someone who is curious and loves him. Maybe there is something in his deepest desires that could come to light in this discussion and be of benefit.