I (21F) and my boyfriend (22M) have been together for over a year, and will be moving in together soon.  Our relationship has been great thus far: we have great communication, have had very few arguments, and are great supports for each other.  We have completely separate finances, but make similar amounts of money and live comfortably.

Since we are moving soon, we have been talking about certain details like cleaning schedules, paying for rent/utilities, and general rules, just so we are on the same page before we are living together.  One thing that has not come up yet is how we are going to pay for groceries.  I have a quite expensive taste in snacks and drinks, and there’s not a lot of overlap between snacks we like, so I would not expect him to contribute to things like that.  However, we plan on cooking a lot of meals together, which obviously will be shared.

Here’s where the issue arises: he typically eats DOUBLE what I do.  His definition of a “small portion” would be my entire meal.  I’m fairly small (at least from a weight standpoint), and he is over a foot taller than me and almost double my weight.  He’s not overweight, just needs a lot more food to function.  I know it isn’t his fault that he is the size he is, but I also don’t necessarily think it’s fair for me to pay for half of the groceries if I’m not going to be eating the full half of them.  Instead, maybe we could do something like 60/40 or 67/33, just for the food for meals we will share.  

I did run the idea by my parents and my best friend, and they seemed to think it was fair.  However, I have not brought it up to my boyfriend yet.  I wanted to gather some outside opinions before I do, because I know there’s a chance I’m out of line here.  I also don’t want to start an unnecessary argument, especially if this idea isn’t fair.  So, WIBTA if I asked my boyfriend to pay for the share of the groceries he would eat? If not, how do I bring it up to him without sounding like I'm trying to weasel out of paying for groceries? TIA!