Recovering Anorexic

I've recovered from being an anorexic and haven't tried to stop eating in a very long time, but I still have a bad body image where I look at myself and all I see is how fat I am, even though I am a size 6 now and at a healthy weight. Usually I can cope with this, but it's been really bothering me lately and so I reached out to my current boyfriend of a year and a half. He tells me that I look good, that he doesn't think I need to lose weight, but if I'm really unhappy I should try to lose the weight by exercising. He doesn't understand that if I tried to exercise, simply to lose weight, that there is a very high chance I would relapse into my anorexia. I told him that I have limits, and he said that I can do alot more than I think I can and that I'm not trying hard enough. I know he loves me, but it really frustrates me that he doesn't understand. How can I explain this to him in a way he'll understand?