Infidelity

Being a massive sports fan, the past year has been full of infidelity. With John Terry, Ashley Cole and Tiger Woods all having to admit that they have been unfaithful, after the press got hold of the initial stories.
http://abcnews.go.com/Entertainment/tiger-woods-scandal-tabloids-allege-woods-affairs-women/story?id=9232973.
Adultery is almost unforgivable. Once you have entered a relationship there should be no doubt in your mind that this is the right person for you. The issue I wish to cover is not, is infidelity is bad? because that's blatantly obvious. But what acts constitute as 'unfaithful'.
Obviously sexual activities with another person, whether its intercourse or blatant flirting and enticing are classed as unfaithful, and rightly so. However, masturbation and looking at porn is another mater. By doing this things, you aren't bringing someone else into the relationship, they are more personal and isolated activities, so i believe there is nothing wrong with it.
Being a man, we spend quite a lot of time doing these last two things, whether in a relationship or not, a mans gotta do what a mans gotta do.