Tara Duncan
Seriously though. Simple solutions. The car will be towed, or it will not. You have done your best to make this a non-issue - keep doing that. If your wife asks if they can tow the car say "no, it's taken care of". It is in as much as you have done everything you can to prevent it.
Worrying, or blaming you for something that hasn't happened will do her no good. She can concentrate on being a good wife and mother. She then views you as having done the "manly" thing - solving problems, keeping the family safe, and hopefully your life moves on. In the possible but unlikely event that the car is towed, you should show surprise that this should happen as it has been "taken care of". You resolve to correct the mistake. Repeat as necessary. Move on.