Partner keeps making comments about weight gain.

Ever since we found out I was pregnant his made these small comments about me "looking after myself" 
It's as if his paranoid I'm going to put on too much weight.. 
His recently started telling me stories about other girls he knows that have "gross" stretch marks on their boobs and has now started showing me photos on facebook of people he knows that are pregnant and says "they don't even look pregnant they just look fat!" 
I'm pretty little and have always been even after having our first daughter but his comments are really hurting me! I'm VERY body conscious and have struggled with this my whole life.. 
I'm feeling pretty down and his just making me feel worse!