You get those kinds of viruses from being on those kinds of sites. So maybe he thought he wasn't lying when he said he wasn't searching porn, because he wasn't searching it right then, when the pop up ad showed up. That's being technical, of course, because he obviously knows you don't like him looking at it.
Okay, so I've been with my husband for 17 years and we've been through this. There is no way in hell you're going to get this man to see your side of it, because porn is simply something completely different in a man's mind than it is in yours'. He doesn't want to hurt you, doesn't want to be pestered by you, feels it's an invasion of his privacy like masturbation would be, and frankly doesn't see anything morally wrong with it. The way a typical man sees it, this is something he's been doing since he was a teenager and he doesn't understand your sensitivity to it. Because we women (I am speaking wholeheartedly for myself here) feel like if he's looking at it, we are not enough for him, we are not pretty enough, not sexy enough, not in-inhibited enough, not loved enough by him. I know how you feel. But the truth is while we feel completely offended as if we've been replaced, he sees his porn viewing as something completely separate from you. It has nothing to do with his attraction, affection, loyalty (in his mind) or love for you.
Spiritually speaking we know this is a bunch of bullshit. But in all practicality, this is really how he sees it and he is nearly innocent of anything bad we ascribe to it. However, if you're a religious person, then I'd tell you it's probably a sin, but there's a really strong push at men to buy into this culture, and they've been doing it since a teenager as a rite of passage and then as a life-long habit. Sorry, but this is the cold reality. Although it's not as bad as you think, because he sees this as entertainment and not having anything to do with your relationship.
I have a friend who was completely completely convinced that since she caught her husband and yelled at him about it, that he wasn't doing anything since. Uh-hmmm. Yeah, I thought that at one point too. Nope, they will find a way because complaining about it they think you're trying to control that private aspect of them and they think the fact it threatens you is silly because to them, it is not a threat to you. So they just go underground and hide their viewing. So my friend (just as I at one point) realized he was still looking at it.
But you know what? The whole time either her, or I, thought they weren't looking at it, we were happy. Our marriages were good and there was no problem. So maybe just chuck it out of your mind. It's not meant to hurt you, it's not reality, it can't really hurt you unless you let it.
It's a tough thing to deal with, but you learn to deal with it and then it's okay. When you get busy with a kid, or more kids if you have one, you really won't even have time to worry about it.
If it's impacting your sex life, though, you got a leg to stand on as far as complaining. I had to do that too. I said it hurt my feelings that he looked at porn and we hadn't been intimate in (at the time) two weeks. He denied it took up his time but I really made him look at how much time he spent on it during that period and he knew I was right, and we got on back on track a little bit. I mean, it's just a crappy thing in our modern world, but we have to do the best we can because this should not be ruining our love for each other. Don't let it win, don't let it ruin your relationship.