This is probably the worst advice you can get – if there’s some sexual interests at work or in your social circles, you might want to get into an FWB. It’s not a good path to take by any means but it might change your thinking. The end fact is you want some action, wifey ain’t giving it so you’re stuck between wifey and action.
I’m not legal expert but at some point, your cheating (FWB) coming out could work both ways. It could either get her to try more or set the path for a mutual divorce. And let’s say your FWB doesn’t go well, you might either realise you love her more than your need for action or you have something to work on for yourself.