My bf thinks I'm "cheating"

Lately I've been trying harder to put myself prettier.. my bf thinks I do this because of college and he always assumes I'm seeing someone, when the real reason I do it, is purely for him to notice me! 😑
I always tell him I have nobody else and he is still not very convienced, but I like the fact that he becomes more protective towards me, that's exactly why I am doing it...
He is always mentioning how beautiful other girls are and how they have a "good body" and he hardly ever says that about me.. in fact he says "i'd like you to have more curves" or "you need to eat more to gain some weight" , "you should go gym to tone up".. and it really puts my self esteem so down.. so for the past month I changed and I've been putting nicer clothes on, looking after myself much more and I really pretend I am trying to impress someone.. is the only way he will "notice" me and value for who I am... it's really sad that he just forgets to look at me in that special way, probably because we are everyday together :(