The grass may look greener on the other side of the fence, but you have to decide if it's really worth killing off your own yard to get it. It sounds like as stav said, it's a fantasy. Something new, something different for both of you. It sounds like reconnecting with your wife is needed and having lengthy conversations with her would help. Date night sounds like a great start!
The hurt will go away and someday you will be thankful you didn't follow the urge to cross that line of no return.