He obviously doesn't want to understand enthusiastic consent. The teenager said "maybe" she wanted to continue? I'd say that a teen girl saying "maybe" is a "no" but she's too intimidated/scared/not sure enough of herself with good boundaries to actually say No.
I don't care if people are into any sexual pleasures that turn them in. But I do not see that the average 18/19 year old girl who is in a relationship with a man 10+ years older and who is a sadist can ever truly consent. I would expect that she is in some vulnerable category too.
I hope to goodness he gets a long stint in the male estate.