Whatever you do, don't read this Pharyngula post. It's all about porn and sperm motility. Myers offers this question: "Do you need a good excuse to give your significant other when she catches you browsing porn sites?" Well, sure, we all do, but Myers's answer is problematic, at best:
Now when your girlfriend or wife finds you at the computer, coffee cup in hand, browsing some hardcore porn site, you can tell her that you are just trying to enhance your virility -- and you have the statistics to support it.
What's the problem with that? Something I read in Dan Savage's book few years back:
[H]usbands may bring wives to their first [swingers] party, but it's wives who drag husbands back again and again.
So what's in it for the husbands? The wives in swinging couples get multiple partners and an evening of orgasms too numerous to count. Beyond the obvious (and not insignificant) perks of variety and novelty, why would a man want to watch other men bring his wife to orgasm after orgasm? Especially when he can have only one himself?
...Researchers have discovered that human males are programmed to ejaculate more sperm when they know or suspect their female partners have recently been with other males.
In other words, if you go with the "I'm doing it to enhance my virility" excuse, you are exposing yourself to the "I'm banging other guys...to enhance your virility" defense. And that's more effective than Bonetti's defense in rocky terrain.
Here's my advice -- don't get caught. Plan ahead. It's like reaching over to unlock the car door (before power locks). Respect, eh?