Though I'm not a full-fledged foodie, I do really enjoy cooking. And I love cooking with a bunch of healthful, flavorful ingredients. Using all the textures of fresh fruit and veggies, for example. Experimenting with new grains and new methods of cooking. I made some (low calorie/lowfat) stuffed red peppers that BF told me looked like works of art - and were delicious, too! And it's not that I'm trying to substitute my healthier foods for those mashed potatoes with heavy cream and butter or the deep-fried batter-dipped fish or the buckets of pasta or whatever... it's just a different, equally delicious thing. Rather than focus on the things I "don't" eat I try to focus on all of the wonderful (healthy) foods I do it. And if I eat the healthier foods most of the time and the others only once in a while it will balance out...
But that's not really the subject here, I know, and I doubt you'll be able to convince your BF of that, 3beans.
First I just wanted to ask, you said in your initial post that your BF is willing to pitch in w/ cooking but won't change his cooking ways. Have you sat down and had a talk with him about this, or are you just assuming? It sounds like he's set in his ways but you never know, talk to him and asking him to compromise might be worth a try. Maybe you could ask him to help cook and tend more towards "your way" most of the time and have a special Saturday dinner where he gets to do it "his way" or something like that.
But if you haven't, I second the great suggestions already made. You can try to eat small portions of what he cooks and eat large portions of filling vegetables or whatever's most on-plan in the meal. But if this isn't working (of course it could work for you, but I know it wouldn't for me), then cooking extra on your nights to cook and making it clear that that's your food for his cooking night will work. I just think it's important to keep communications open. e.g. "Honey, I do love your food, but it doesn't love my waist, and losing a few pounds is really important to me right now" or emphasizing health, "Honey, I love your food, but the butter and cream really sap my energy before my evening workout" etc.
Good luck!