Ciaran, great question! She is manipulating him to get her way. She is approaching the issue from scarcity and intentional depravation. Can you imagine if he, as the provider (if he is), said, "I'm not going to pay for anything you need until you do things my way"? Or, "I'm not going to talk to you until you do what I want?" Can you imagine? Imagine that outrage from feminists. Even if this works and he handles things the way that she wants, he won't forget it and he will resent her for withholding. Without even knowing exactly why, he might even divorce her years later because of the damage this will do to their connection and emotional bond which is the exact opposite of what sex is - which is union and bonding. Even when a couple doesn't agree or is having issues, sex is what can keep them close and cause both to feel connection and understanding which can eventually help them work with each other and have more understanding for each other. Withholding sex creates resentment, distance, and a feeling of being in opposition to each other. She is playing with fire but because it is attacking a man, some women will support her. It's sad.