It sounds to me like this guy is also insecure about aging himself, so much so that he is willing to beg you to be some ideal woman. I am not angry at him as much as I feel sorry for him. I mean, he really must feel like life is passing him by so if he can't grab the golden ring in life himself, like his career, looks, how much money he makes, etc. etc. then if he,
at least, has a model wife he has "acheived" something.
I think, I would really have an open and honest talk with your husband. After all, you two have children together. I am assuming that you have weathered some storms in your married life together. This could be another one.
I agree with the others here who say that first and foremost you need to focus on what makes you feel good. If you lose weight for someone else, if you don't get the response you expected from them; ie, constant attention or fawning all over you, then you are less apt to continue to remain thin and regain the weight.
I used to want to "show people" that I wasn't the loser that I felt that I was when I came to my weight. Ironically, it took me finally dumping the "people pleasing" part of my personality and not give a **** what others thought to get me in high gear to take care of my body and lose the weight. The benefit of that is that I know why I am doing what I am doing. It also helps me when I see other people making different choices than I do regarding food. It gives me a feeling of inner strength. I don't feel superior but I do feel good that I am choosing to take care of me.
I hope you will consider taking some private time and sorting through some of the feelings and thoughts you have expressed here. There is no right or wrong way to feel about this. Maybe, helping your spouse to deal with his feelings of insecurity will help you both in the long run. Also, counting your blessings. It sounds like you and your family are in good health. How would he feel about you if you had a car accident tomorrow and your beautiful body was no longer able to walk or run? I just think we waste a lot of time comparing ourselves to others when we are just fine as we are.
Tell him to be thankful that you are what you are, that you care about what he thinks and feels and then see what he has to say. It's not a crime to be shallow but it is a pity.