Infidelity in marriage If you are in a sexless marriage where your wife absolutely denys you any sex or intimacy no matter what, is it OK to cheat?  What is the Buddhist rules on that?  I understand that my wife's behavior can be considered sexual abuse.  What she does for me is actually not good for my health and well being.
You don't need to have sex to be healthy and well. Otherwise, most Buddhist monks should be sick. Cheating breaks the 3rd precept. That is bad Karma for you. 

Whether your wife agrees or not, associating with prostitutes has many bad consequences. You and your family's reputation can be tarnished. Higher risk of catching diseases. Your wealth will decrease. You could be cheated in many ways as you have very little idea about the character of the other person. You could be blackmailed by those who get to know about your habit. Most of all, your lust will increase. After sometime, you will start developing unnatural sexual cravings. There's no end to it, if you crawl down that pit.

Nevertheless, sexual pleasures are not forbidden for lay people. So, as a Buddhist layman, you have several decent options available:


Try different socially acceptable methods like being romantic, changing the environment, buying presents etc. and see if she changes according to your liking. 
Talk to her, let her know that you are not happy and take a decision on the future of your relationship, if she doesn't change.
Restrain yourself and try to focus on your spiritual development as having sex doesn't bring you true happiness.