What’s his relationship history prior to you?
Also — was this one browsing session/rabbit hole or was he repeatedly viewing these videos over a period of time (months or weeks)?
I find it a bit odd that a 56 year old man in a relationship is watching these dumb videos, but I agree with PPs that the YouTube rabbit hole is real and would be embarrassed if anyone looked at my browser history. Because I’m a closet weirdo.

But so are a lot of people.