I have to say that if my ol' man and myself were in a similar situation, and I caught him throwing a set to me so that I could win....I would be pretty freakin' pissed off!
I have worked very hard to get my game to the level it is now, and expect to be treated as an equal, even by friends and family, once I step to the table. I would consider anything less as patronizing, and that is was would get my ire up.
If I am not the better player in any given game, then I deserve to lose that game...pretty simple concept to me. Once you get to the table, any relationship you may have with your opponent should have absolutely no bearing on how the game is played.
I would be more worried about how the wife will react when she finds out, (and she will), that the only reason she won was because you dumped to her!! If you beat her outright, she may be a little upset, (although she shouldn't be), but the bottom line is, that's pool...
someone has to lose.
My guess is, if she is anything like me, she would be more upset with herself for losing than she would be at you for winning...and this will push her to work harder at getting you the next time.
Lastly, please remember that it is just a game, and it should not be something that is carried back into a relationship.
Best of luck to both of you!
Lisa