The self esteem is something you would need to foster internally. Self care (doing things for yourself that make you happy, relaxed, feeling sexy, etc. are something to explore. When you do them, you do them for yourself not him. Whether it is getting your nails done, getting a new outfit, getting a massage, etc. Try to see yourself not just as his partner but also as the woman you are whether you are with him or not.
If you melt in front of him, that may give him something negative to focus on. You would want to try to start re framing your thoughts about yourself (if you catch yourself being negative, change it to something positive- something that you have control over. You are correct- you can not change him only yourself. He is but one person afflicting you. Your whole demeanor and self esteem should not be based on that. You are more than his opinion of you.