It seems your unhappiness with your marriage and your husband's behaviour need to be addressed before the issue of losing weight.
If you were happier it wouldn't be as hard to lose weight. You would need to quit drinking alcohol or have only 1-2 drinks of wine max per week; wine& alcoholic drinks are full of calories. Plus, you'd need to go the gym 2-3 times a week for an hour or so, as cutting down food without exercise doesn't usually work. Walking also helps a lot. You could also take up yoga or dancing or swimming. Anything you enjoy which will help you lose weight.
The above tips will help you. But ultimately you have to lose weight for YOURSELF- FOR YOUR HEALTH AND SELF CONFIDENCE. NOT FOR YOUR HUSBAND.
If your husband was concerned for your health only that's understandable. But he shouldn't be criticizing you and making you feel bad. You're his wife- and regardless of how much you weighed when you got married- he took a vow to stay with you for better or for worse. Also, people get old and sick all the time. How would he feel if he put on weight or lost his hair and you were unsupportive?
You need to sit your husband down and explain that you're unhappy with the way he's treating you; that being critical and comparing you to other women is unacceptable. He needs to go to counseling with you to work on issues related to the marriage. He could be using this weight issue as an excuse for other issues. If he won't go, then you need to go alone so you can decide if you want to stay in this marriage.
Once you feel better and you've made a decision about your marriage, it will be easier for you to go to a gym and cut out drinking so you lose weight. But it will only work if you're committed to it because you're doing it for YOURSELF. If you're not and it's not a health issue, then there's no point trying to lose weight. If you DO want to get slimmer, then it's also a good idea to walk and go to the gym with girlfriends who are supportive, so you feel better.
Remember that everyone has a different body type and a different metabolism, so don't allow anyone to compare you to others. We're all unique.
I hope you lose weight for your health and confidence- and that your husband either learns some compassion. Otherwise, you should lose him along with the weight!:)
Show him this letter if it helps. Good luck.