I'm mixed on it.
Porn is harmless to a relationship and can actually be quite fun if shared between the two partners... and should be within reason.
BUT, women who get upset about men who watch porn and masturbate instead of being with them, need to put their woman-ness feelings down for a second and try to examine why. There's a reason why the man is doing that; maybe he feels something is lacking or there's a desire that is not being fulfilled. He doesn't intend on cheating on you, still loves you dearly (usually), but is either not confident enough, or too complacent in his life to try and ask you (the female) to change your ways to satisfy him... its just easier to relieve a little stress with a 5 minute toss job.
Without being condescending or awkward about it, the couple needs to talk about what is not right in the relationship and reach a comfortable medium as to what they can do to remedy it. If that medium cannot be found, which sometimes it cant, then it needs to be understand that every now and again, that man is going to rub one out.
The women that get upset about it think with their estrogen. Men aren't wired the same emotionally. There is no emotional attachment to that as a woman suggests, so the idea of "cheating" isn't even an issue. Its more of an issue of working off pent up frustration, relieving stress or just simply, because it feels good to play with it and he was all alone. Men are visual by nature, so watching someone do things they enjoy is the easiest way to get aroused.
