Am I being vain?

My bf wants me to get a huge belly and I feel I will since I'be been showing since 8 weeks. I'm overweight and my doctor said I can gain up to 25 lbs. I said my goal is 11. This really upset my bf even though the Dr said that's fine. I refuse to over indulge and I'm not starving myself. Just eating healthy and until I'm satisfied opposed to stuffed. My belly is growing nicely, I'm losing fat in my arms, legs and face, I feel great.

Does anyone else's spouse give them crap about stuff like this? Am I being vain?