Fiancé thinks I look too skinny

I went through a period of severe depression after trauma and gained 40lbs. The past year I've been working hard on getting better emotionally and I've lost ALL the weight without any crazy dieting! I feel confident enough about my body that I'm even looking forward to summer clothing. I'm a much healthier and positive person, but my fiance has been going in the opposite direction. He's constantly negative and depressed and our relationship is about to fall apart. For the first time, I took off my shirt during sex yesterday because I finally felt confident enough. He just glanced and said "you're too skinny" before trying to force me to continue. That broke me a little. We're going to couples therapy next week....any ideas how to explain this to the counselor? Idk if I sound too whiny. 😕