You should have set the ground rules when you first married the lady.
RULE: I control the finances, you don't like it the wedding is off!
*note* When stating this rule stand a minimum of 10 ft. away, wear a cup just in case she can jump and kick and make sure no heavy objects are nearby that can be used as weapons.
Do as the boys have suggested, hoard a little bit of money every week. It should get you an SP every 2 months. If your wifey knows nothing about cars, make up some fixes. Tell her the water pump is gone and you are catching a break if you pay cash. That should be good to get you a session in.
Be very very careful if you cannot lie without it showing on your face, you will be hanged sliced and quartered in your sleep!