He is being insensitive. If my husband said this to me, I'd be very shaken. That said, I'm going to give him the benefit of the doubt here, and assume that he a) has no malicious intentions, b) loves you to the ends of the earth, and c) is a great husband generally.

Working from those assumptions, here's what I'd do in your shoes.

I would crack open a bottle of wine and set up the computer. Open your browser to http://theshapeofamother.com/. Minimize the window.

Call your husband over for a glass. Tell him that you know he didn't mean to hurt you, but as you told him in your letter, it's weighing on you still, and if you two mean to become biological parents together, it's important to you that he have a good grasp on what this means, physically, for you. It doesn't mean you'll be destined to stay overweight, but it DOES mean your body might change. Hips widening, boobs sagging... is he cool with that?

If he says he is (AND HE SHOULD. If he says otherwise, my assumptions are null and void, and you should reconsider spawning with this dope), then say, "Okay, then let's get educated together here, so we're on the same page. For my sake, I want you to look through this gallery with me."

Then pull up http://theshapeofamother.com/ and look through the entries. Some are "worst case" scenarios -- really difficult births, heavily overweight; some are "best case" scenarios -- easy births, moms are in size twos and fours, six months later. Look through a bunch. Get a sense of the possibilities, and the general changes that affect almost ALL women (stretchmarks, saggy bellies) after birth.

Read the commentaries from mothers who aren't entirely comfortable with their new shapes, but so in love with their newborn kids. Pay attention to his reactions, as well as your own. Talk about them.

I don't want children, never have. But even I know that this is a major, life-changing journey you'll be setting upon, and YOU will be the one to bear the majority of the physical changes. You need to get him on board, as a partner and enthusiastic team member. It will take his support, when you have a small child, for you to get to the gym, much less to parent effectively.

This red wine and internet-surfing session could be the first step toward cementing that teamwork, honesty, and empathy that you'll need to keep your marriage strong and healthy as you become parents together.