Bf watching porn!

So I was in the room and was on my bfs tablet and I went to go exit out of my opened apps and seen that he has been recently watching porn on porn websites. I don't think it's the first time because he never has his tablet by his bed and recently he has. How am I supposed to feel about this? Should I let it go? Is it a big deal? It kinda makes me feel gross like why is he watching that kind of stuff when he's with me? Opinions please? He's an older guy so I don't know why he'd be wanting to watch that when he has all that right in front of him.