Hitchhiker: I sympathize with your situation. No fun when both spouses are unhappy with the family finances.

As for the pure financial picture, my suggestion is that if you aren't brave enough to have the conversation with your wife, then you need to get another job so you can afford the life your wife wants to live. Then the FS problem will go away. Of course, you will probably have a DS or FC or lack of UA time problem to address, but maybe you will find those topics easier to address with Radical Honesty.

As for how does a couple who fights over FS stay in love, surely you cannot expect me to have an answer to that. I can't even remember what it felt like to feel romantic love for my wife. Now, if you ask me how to keep the cold dark flame of frustration and resentment alive, THAT I can wax poetic on all day and night. But love? All I can do is refer you to that Tina Turner song from her Private Dancer album.