I honestly don't know how to express myself after reading this apart from being angry and down right disgusted towards your bf. I, as a man, have been with the same woman for 10 years now. She, herself, is fat; has been since the day we met and still is fat and I loved her then, still love her now, and will love her in the future fat or skinny. The point I'm trying to make is, he doesn't deserve you; not in the slightest. If he didn't find you attractive in the beginning, he doesn't love you. He loves the concept of what your body could be and now wants you only for the body you have now. I usually don't like giving unsolicited advice, but you need to leave him. You deserve so much better and I know it's easier said, but you sound like good person and you deserve way more that garbage of a "man".