Okay. There is just SO MUCH to say about this situation, I don't even know where to begin. So I'll just throw out some thoughts.
First off, please please PLEASE do not bring a child into this situation. If you and your husband decide to work all these huge issues out and work together to create a stable, happy home, that's one thing. But it is so unfair to bring a child into a home where the members make one another miserable. Seriously, please do not inflict that kind of damage on an innocent child.
Next, the fact that your husband took a cheap shot at your weight shows he fights dirty. That's poor form, shows poor character and a lack of love and respect for you. The fact that such a cheap shot hit a nerve shows that you have work to do on your self-esteem.
And before we go further into THAT, let me say my father's family also has a tendency toward being overweight. And I am so very much my father's daughter, both for better and for worse. So I feel your pain on that front. Very much so. In fact, I think I'll start a thread on the topic. But in dealing with the issues before you, you and you alone must deal with your SELF-esteem and SELF-image.
One final thought: when my brother and his wife of almost 20 years divorced, they shared the house until they could sell it. Took almost two years. Yes, there was some wailing and gnashing of teeth on both sides, but they're both smart, strong people and they worked through it and in the end they came out the other side as friends. Now they have a much healthier relationship than most ex-spouses.