I love the usual advice, "dump him", "just move on", "if he doesn't love you as you are" etc etc and all that. However in order for someone to love you/fancy you, you must love and fancy yourself. In other words be comfortable in your own skin. Your partner should always support you (the decent ones anyway, sometimes telling you somehome truths), however in order to be loved you must love yourself (in a non ego central way), and find happiness in your own skin. And if you then feel that someone doesn't give you the love you truely deserve, then dump them, and find the love you are truely worth.
You know what the answers are, as you ask for the answers in your own questions. You know in yourself if you feel fat, unsexy, unconfident, that you must work on these first.
My advice. If you were as ship sailing on the open ocean, you wouldn't drill holes in your own boat. So why drill holes in your personal boat.
Learn to love thy self, and work on your own insecurities. Eventually men, women, people will be attracted to that inner self, sense of importance, that you matter.
Love and well being to you all. xxxxx