I really don't understand...

I really don't understand why guys in relationships always want to go to strip clubs and watch porn...like really? You have a wife or your girlfriend what do you need the extra for? Now I know its not just guys and girls do it to, but I just don't understand it. Why do people always have strippers come to their bachelor or bachelorette parties? Why do guys always seem to flirt with every girl them meet? Why do guys constantly check out other girls? Why do guys lie about these sort of things? Its like we understand there are prettier girls out there than us, why rub it in our faces? Even if you don't know we pay attention to little things like that? Why are guys so focused on girls and sex?

I think about these questions all the time and I would love for someone to answer them for me...

I don't know if I'm the odd one out who believes all these things are wrong. I understand that there are some girls who do these things too (a select few), but really...guys do it all the time and its like all guys do at least a couple of those things on a day to day basis. I don't know, it frustrates me and makes me mad...