Interesting question. I don't think these things lead to infidelity, in and of themselves. However, the mentality that causes someone to frequently seek out someone other than their significant other to lust after is not really conducive to remaining faithful. Some people get addicted to that thrill of "attraction" and it can lead to their seeking greater thrills by "hooking up" with others. There is another aspect to this. Many women are deeply troubled by the use of porn or visits to the strip club by their partners. They end up arguing about it with their partner. He, in turn, thinks she's nagging or controlling and, rather than trying to find a way to fix the problem, he clings to it and, sometimes, uses it even more. This drives a wedge between the two. Because she cannot comprehend why he is doing this when he supposedly loves her and is committed to the relationship, she may develop a severe complex about herself. She'll feel unloved, unappreciated, unattractive, and sexually inadequate. As a result, she could turn to someone else in an effort to fill these holes, particularly if that person gives them positive attention (not just trying to get them into bed). The man, on the other hand, may get to feeling that she's not the same woman he fell in love with or, "She already thinks I'm doing it, so I may as well actually do it." I actually think that some of these issues may have been factors in the detonation of a friend's marriage. The bottom line, porn and strip clubs are not responsible for infidelity, the people in the relationship are. They may, however, be symptoms of a problem that could lead to it or contribute to the situations that ultimately do, particularly when they are not engaged in as a couple, but are, instead, used by one of the partners to the detriment of the other.

In my relationship, it is shared between my lover and me, and no it leads to more intimacy.

I don't go to strip clubs but for me, porn helps prevent infidelity. My girl can't be with me 24/7 and she is not always in the mood so watching porn relaxes me when I can't have sex. If I didn't release myself I might start to go mad and do something I would regret like cheat or seek out someone else. As long as I am taken care of and am to ejaculate, I am satisfied. Porn is only a safe fantasy.

This is an extremely complex question! Raindancer is right that it does depend on the choices of the person. However, the easy availability of porn online can also come into question. As for strip clubs, I have nothing nice to say.

Porn is 99% for men, and I have used it, am a man, mostly when I am not getting any sex, or when a girl sees me once a fortnight, say, or am I in a long distance email r'ship, like now..... it's mostly to replace the act of sex for us.... that's all it is. Strip clubs.... frankly, the ones for men are stupid, handing over money to be teased.... senseless. Strip clubs for women actually often cater to infidelity, the women actually fucking the strippers onstage... almost all of them suck at some point. The problem is that they don't allow their men to have any fun... and when they go back to their men, there is not the same excitement for them as having sex in front of their girlfriends.