Hi and welcome.

It depends on the dynamic between the three of you how you want to deal with the junk food situation... Do you do all or most of the shopping? How about the cooking?

I deal with it by basically making it my SO's responsibility to buy his own junk snacks, and then accepting that it's simply not mine to eat. Would you steal money out of the ten-year-old's piggy bank, or your fiance's wallet? That might sound like a harsh analogy, and honestly he wouldn't care if I ate some of his chips, but that's how I think of it and it generally works. It really does keep it off my radar. I don't even bother looking in his snack cabinet.

...so that's where I would start. Maybe have a rule that all of the junk food stays in one cabinet, and you'll stay away from it. You deserve their support - treat it as a serious medical situation, not just vanity. I'd eventually take charge of the kitchen and meal-planning, too.

Another important trick is to make your food as appealing as you possibly can, just as good as theirs. It's well worth the extra bit of time and money. Your success will probably depend on this.

Then, you just have to Sam Malone it. You're an alcoholic running a bar. It's hard, but you have to train yourself to accept that even one bite - one taste - one little lick of the knife - is "the kiss of death", as Dr Atkins put it.

For the record, I "get" how difficult this is. I had nine years of 'bliss' in which I had total control of my kitchen and no food at work, but I just celebrated my third anniversary at my current job - making donuts, muffins, cookies and danishes for a donut store in which we're all allowed to have as much as we want (and all of my coworkers do.) I have not once eaten any of my products. Yay me. But - I've had some of the ingredients like donut fillings that are gluten-free, and it's led to a binge every time. It starts with one little taste, and I tell myself "that's all I'll have" or "I'll skip dinner to make up for this." It's a huge mistake.

Good luck.