To be fair, he prefers porn over videos of me/Videos of us having sex.

I guess as long as he prefers you over porn when you're together, that shouldn't be a problem. I also act the same way when I'm masturbating and about to see my SO soon, and heard the same opinion from other guys. I do find her beautiful, and amazingly hot, but I choose to fap to pictures of some stranger because masturbating while watching pictures/videos of someone takes away a little from the person's sexuality and makes the sex next time less enjoyable.

So I'd only fap to GF's nudes when we won't see each other for some time for some reason.

His reasoning sounds like he also could have a porn addiction though.

I completely understand how you can be not comfortable with him watching porn of milfs with huge boobs and butts. That's why I'm not discussing my porn habits with my SO, I know she probably won't be particularly happy about it. It's an insecurity many people have, and so does he - that's why he's not okay with you going to a strip club.

And I agree that it's a double standard, and doesn't sound healthy.