How should I react to my boyfriend's comparing me negatively with other women?

My boyfriend likes to make comments about other women’s features while he’s with me. He prefers women with perfect figures and women who are African-American. I am neither perfect nor African-American. What is the best way to respond so that I don’t make him upset? I’m constantly being compared to other women, and the implied conclusion is that I’m too fat and not pretty enough. I’m working on losing the little bit of belly fat that comes from having children, but I can’t change my nationality. I’m too scared to lose him, but I don’t feel worthy to keep him. He likes the sex, but doesn’t get romantic and rarely kisses me passionately. If I hear anything about myself, it’s always in a negative light. I COULD be pretty IF I did these particular exercises, for example. Do you think he would “wake up” if I didn’t talk to him as much, didn’t compliment him, or didn’t tell him that I loved him before he went to sleep? (He doesn’t tell me he loves me. He will tell me that he loves me, too, IF I say it to him first.) Or would it likely damage the relationship?