Calorie Count question, and I think I need "fewer"

Okay, well, the calorie estimator thing says that I should eat 1,200 calories per day to reach my weight loss goal. But truth be told, I never did eat a lot, probably 1,600 was what I was eating, and I am 5 foot 9. This past winter with NO changes to my diet, I experienced increased belly size and around 10 pound weight gain. To me, it seems like I don't eat a lot, I always eat "healthy" food (like plain yogurt, muesli, mixed greens, chicken, homemade soups, and such) but I still look matronly.
My husband eats (this is not a joke or exaggeration) around twice what I eat, and he is the same height as me, and is very very slim. And no he does not exercise at ALL. The program said "you must eat more or you are starving yourself" because I have been around 800. I don't believe this, because I think that for ME I would have to eat pretty much nothing to hit starvation mode. Any thoughts? Any advice? Should I eat more?