The easiest way is to get them to cancel the membership. You'd need to get your Mrs to breach one of their own policies.

As an idea, you could get her to make a pass at every woman in the changing rooms. If one of them accepts, this could be a win/win for you whatever the outcome. Smoke crack in the jacuzzi, take a running piss on the treadmill and claim she's training for a double marathon, answer everyone's greetings with "CUM ON MY FACE" really loudly?

It could work.