My husband is twice my size, vertically and horizontally. I gained 30 pounds when we moved in together because not only did I start eating like a 200+ pound man all of a sudden, but I also quit smoking since he's a nonsmoker.
Now, we don't eat the same foods anymore at all. We no longer cook big, unhealthy meals together, and when we go out to eat, I get something healthy and plan what I'm going to get at the restaurant ahead of time, and he gets whatever he wants. I put it to him point blank when I started on my weight loss regime if he actually cared that we didn't eat the same stuff anymore and he said no, that I could've eaten as I wanted all along but that I seemed to want to "nest" and do the domestic stuff together early on. He couldn't care less if we get two sets of groceries and eat our own way. For me, pre-defined portion sizes are the only way I can manage to stay in my comfortable weight zone, and he's fine with it.
This is not to say we won't still cook together but we've lately been only using that as a special occasion thing, and that makes it more special anyway.
