It’s also common for women who are turned off by their fat husbands to withhold sex as a punishment, or an incentive to lose weight.
I was once in a relationship with a man who stopped doing anything to take care of himself — he went from eating healthfully and walking and bicycling all the time — and he had a terrific body — to sitting on his butt all day and eating nothing but carbs. I stopped having sex with him not as a punishment or to motivate him to lose weight but because I just wasn’t attracted to him anymore. I didn’t think sex with me was something he was entitled to if I wasn’t attracted to him. I wasn’t “withholding” sex. I just didn’t want to fuck him and didn’t see why I should.