He serves you the same portion sizes as he eats
There is a reason why men are told to consume more calories a day than women (2,500 to your 2,000, since you ask). They're bigger, have more muscle tissue and require more energy and fat to get them through the day. It's therefore okay for him to eat man-sized portions at mealtimes, while you should be tucking into a smaller serving that better suits your nutritional needs. But if your boyfriend likes to take charge in the kitchen every evening, he may instinctively present you with the same monstrously oversized plate of food that he gives himself, the surplus calories from which spell disaster for your waistline. Repeat after us: "I must learn portion control, I must learn portion control..."