Would you be okay with your partner watching porn outside of masterbation?

So I was aware of my husband watching porn. But he was talking to his friend and admitted he would watch Reddit porn threads randomly at work while he was using the bathroom to "pass time." I'm not sure why this makes me so uneasy but I have a gross feeling about it and I can't understand why he would want to look at that outside of what the use is for. Not to mention the women he looks at look nothing like me. Maybe I'm just insecure but it really rubbed me the wrong way because I've never watched it outside of masterbating. (Which I don't very often anyways)