It's wrong of him to criticise you and it's wrong of you to think he's preventing you from losing weight. Has he been supportive in the past? People in relationships can be real cunts to each other. Holding a divorce over your head if you don't lose weight is probably a bit dramatic and insensitive but at least he is honest, and he probably feels like this is a last resort. He must really have held it in for a long time. Like, he really must want this lifestyle he does not have. I don't think you should get fit for him but ultimately what he is asking isn't going to be bad for you, which you already know. The only thing that's going to help you is if you forgive him for being a dick and find your own goals for weight loss. And obviously tell him if he really wants you to lose weight, he's gonna need to help you, either by eating healthy with you or supporting your need to have junk every once in a while. Maybe you should both agree on what you consider acceptable amounts of junk to eat. My guess is that every time you eat junk he's thinking "this is why you are overweight" when in reality, that is unreasonable. Many different things lead to being overweight and one meal isn't going to fucking make a diff. You can do this and you know it. Let him know you're really going to try, but you need support, and tell him you don't threaten to end his marriage every time he fucking leaves the toilet seat up so shut the fuck up about that.