This is a complex issue, and it's easy to slide into male-bashing. It's true, we all feel that if you love someone, you should love them unconditionally regardless of how their looks change. That's a lovely ideal, and it is reality a lot of the time. But sometimes it's not, and that doesn't make the other person shallow by default. I would definitely call myself a feminist, but I also know that men ARE wired differently. Yes, men are visually oriented, and yes, sex is a very necessary component of a loving relationship. So, he may be feeling that he's been dealt a double-whammy.
Now, that's not to say you should be intimate if you don't want to, or that you should lose weight for him. I would never in a million years suggest that. Just try to see it from his point of view to understand why he's said what he's said. Then, think about what you want your life to be. A healthy marriage with him, sure. You can't have a healthy marriage, though, unless you are healthy -- not only physically but mentally. So, if your goal is to be the healthiest you you can be, to stop being trapped by your unhealthy body and attitude, then you're on the right track. You've gotten caught in a downward spiral, and now you have to put forth some real effort to reverse it. It's hard. No one here will tell you it's easy. You have to sometimes do things you don't want to do, and not do things you want. But it can be done, I promise. There's a lot more I could say on the topic, but briefly, you have to engage in some positive, helpful self-talk, and turn off the negative scripts running in your head. The demons that tell you you can't lose weight, that it's OK to have a piece of cake, that you can't possibly be intimate with someone because you're not skinny all need to be told repeatedly to SHUT UP, and then answered with a positive response.
To close a long rambling post, I'd recommend these things:
First, pick up a copy of Thin For Life -- you can probably get a copy at the library. This book is the "bible" of the Maintainer's group. Pay particular attention to the chapter on positive self-talk.
Second, I second the idea of counseling. Joint counseling would be great, but if he doesn't want to go, go by yourself. A third part who can help you two talk to each other and articulate your inner dialog, as well as develop strategies for working things out, will be invaluable.
Third, talk to your doctor and make sure that everything's OK hormonally, etc. Even if you'd dropped the weight immediately, it is very common for a couple's sex life to change dramatically after the birth of a child, for both psychological and physiological reasons.
Finally ... I am NOT one to be self-referential, but you might want to take a look at a post I made about a year and a half ago. This thread addresses some of the body image topics relevant here.
A Lesson in Body Image