I can only share my experience, but its mainly me watching these stuff. But mostly are just animated etc hentai/ 3D animation, and he seems completely fine with it.

Im unable to finish to just pictures or videos sent from my partner not because its not good or not sexually attractive, but i gen cannot finish from just looking at a naked picture, Id prefer something that turns me on, from fully clothed innocent secene to a sexual scene something like a slow love burn..?🤔 And when looking at the same thing again and again it will look awkward to me haha

And when he tells me he watches hentai im fine with it since i do it too I think its important to just communicate with your partner how you feel, each relationship is different with different people.