Maybe I fall in the minority of men, but I believe most of the complaints about marriage are due to a mans poor leadership.
-Overall, the savings are minimal, I would say rent/mortgage is saved, but nothing else. Maybe traveling because you can half gas, hotels, etc.
-The sex will dry up if suck in bed or if you dont meet her emotional needs.
-kids are marriage are two different topics, so thays not really relevant here.
As far as other spending, you have to train your woman. This is done only with proper leadership. Any woman can be trained out of bad spending habits. I've found the best way is to lay out their spending, break it down. (Eg. "You spent $100 on Starbucks last month, that's 1200 a year. That's like two trips to Hawaii."). I love running the number game on people in general. My current lady was hemorrhaging money and had about 8k in debt when we started dating. Shes now debt free and saving about 1k a month. I didnt force her to do anything, I just provided a bit of advice and perspective.
When you can provide advice and perspective on multiple facets of a womans life, she will treat you like the father she wants to fvck. All you need to do is plant the seeds and watch the trees grow. Unfortunately, most men are terrible gardeners, they would rather complain about the soil or the quality of the seeds.