Sweetie, I totally feel for you.
My marriage was to a man who sounds a lot like yours. I was at my thinnest since high school when we met, and he had some SERIOUS emotional and psychological issues (parental, drugs, alcohol, etc.) Unfortunately I wasn't enlighted about this until after the wedding. Luckily, (although somewhat sadly) we didn't have any children for him to emotionally abuse, but he sure as heck did it to me. He told me once (jokingly, or so I thought) that if I ever started to look like his mother (who is extremely overweight) that he would leave me. Well, in a year or two of marriage, you get comfortable, and for me, the weight started to come on. And I'm not saying that this was the only problem our relationship had, but it was the one point he would always bring up to blame me for why our marriage wasn't working. So I tried harder, going to Weight Watchers, exercising more, trying to please HIM and make him stay with me. And it didn't work. We separated, and I have been divorced for over a year now.
And now I am losing the weight for ME. And I have found a wonderful man, who fell in love with me when I was fat, and proposed to me when I was fat, and who will marry me when I am (not quite so) fat.
My heart breaks for you, because I remember the me that I was 3 years ago. So first, lose the weight for YOU, then for your children, so they know their mommy is a fighter, and if your husband is worth it, he will realize that he needs to be the kind of person that you are, and if he's not worth it, then you will have tried your best and realized there was nothing else you can do.
Good luck, I know you can do it!