My wife is addicted to co-sleeping. How can I get her to stop?

That is tough! Maybe you could speak to someone else your wife is very close with & them talk to you with your wife. Explain to her she is stunting the growth of her children. Having no independence for their self & start doing things without mommy. She needs to be the parent first & a friend second. Their is no reason a 4 year old should not be potty trained. Try to explain to her she is crippling them & her marriage. And to work on paying more attention to you!