I'm going to chime in here and agree wholeheartedly with Mike. It's the hiding and lying that is the true cheating. If you wouldn't do something with your wife standing right next to you, doing it when you're alone is not okay for the simple reason that it's a betrayal. Doesn't matter what it is...that's your litmus test.
The computer activity might seem like it's not a big deal, but believe me when I tell you that most of us are here because of situations that started off 'innocently'. And as a woman, I can tell you that if my H had been coming to me for entertainment/companionship/naughty talk/emotional support, our R would be in an entirely different place today. I wish he would have. Doing any of these things with someone or something else is a breach of intimacy.
You are quick to admit that the problem is yours--that's great, because acknowledging the problem is the only way to start changing. Real change is tough, but worth it, because this habit is more than just 'looking' at other women...it's a wedge between you and your W. Might seem small, but it won't stay that way. Figure out how to beat this and you can beat anything. Good luck!
