Well here is why I reveal things to my wife. She is my WIFE of 4 years. We have 2 children together and a very strong relationship so I dont see us ever seperating. We were best friends for ten years before we started dating so I know her better than anyone else and trust her dearly. If she was just ( and I dont mean anything by that) my girlfriend than I would not tell her. We could break up next month and she could blab a lot of secrets just to piss me off. Beacuse of the trust I have in her ( and believe me, to trust a someone to be the mother of your children is trust enough to reveal some magic) I dont fear any leaked info, even in an unlikely event of a seperation.
Second, I dont know any other magicians, so I find it of great use to have someone that knows how something is done to be able to critique your perfomance and handling of an effect.
Third, I dont have to hide in a closet to practice my effects or worry about leaving my TT on the coffee table. If you live with a women, sooner or later she is going to learn some things. My TT has been saved a trip to the wahing machine a few times by my wife checking my pockets as well as other things that may not fare so well in the wash.
Thats it in a nutshell. Other than showing my wife how an effect is done, I never reveal anything to anyone...no matter what.
I stand by what I have said!