I'm not even talking about divorces or the cost of children, because those ones even common people generally notice, I'm talking about things like:

1)How often do you go out with her, to places where spending is required? If it wasn't for her, would you be out less often?

2)Would you live in the same house or rent the same place if it wasn't for her requirements?

3)Would you bother as much about house decorating and furnishing if it wasn't for her?

4)Do you travel more because of her?

Stuff like that. Even if you find the odd woman that agrees to share all expenses equally, you are probably spending more than you would be spending if you were single (and women like that are not common).

In general women just make you feel less satisfied with your material possessions, just by her mere presence. That and the nagging and social pressure, not imposed by society directly, but by HER perception of society. In general men are much more fiscally conservative with our spending, women are not like that,and it influences your behavior, it's essentially impossible to avoid all influence while being so close to someone like that.

edit: I realize most MGTOWs do notice that though.