As excellent smooth talkers I am curious how you would deal with the situation that this guy has >> the reddit post

For the lazy like me here is the post...

We are a young family with a 1 year old daughter, no savings, mortgage and some other debt too. Yet my wife continues to do things like eat out for lunch, and get $200 haircut. I asked her to please cut down on her hair costs and she completely flipped out and said it wasn't an option. How can I convince my wife to be more frugal, without pissing her off or alienating her completely? I am somewhat attached to her. Thanks!