Don't look outside of the relationship. If you are at this point where you are seriously searching out some side action, NOW is the time to take action. Talk to your partner about what is missing in your relationship. Suggest couple's counselling. If this does not help and you are still wanting to look elsewhere, do your partner a favor and leave the relationship before getting together with someone else. Cheating is extremely damaging to the scorned partner and is completely unnecessary. Not to mention you are going to crap all over your reputation if and when it comes out. Karma will bite you in the butt one day if you do this, keep that in mind