I'm going to lie to my wife about going to lunch with my former boss.
That doesn't make sense.   What's the reason behind lying to your wife about going to lunch with your former boss?
The reason behind that is that my wife can't stand her.
Lying is probably easier than telling the truth in this case, but it is very wrong to lie to a partner about what you did. Being honest and telling her about it might make her respect you more.
My wife and I have completely different life goals, that why having kids with her is a not good idea. If I didn't like her anymore, who would I tell?
It sounds like this runs much deeper than meeting with a boss.  I would focus on resolving core differences and allow that to help you work through the smaller problems.