I am so sorry you feel so depressed and while I am neither a nutritionist nor SLIM I can offer a few thoughts which you may or may not wish to take on board
You don't say your height, but could you work on how you look (even if you would like to be thinner) - there are some stunning "statuesque" women role models out there- big, bold, colourful and confident. When I look at so- called magazine makeovers, so often the changes are in the clothes (bolder) shoes(heels) hair and LIPSTICK. A former colleague who was a lot more than 16 stone but had a very sweet, pretty face lost about half her body weight on the Cambridge diet and frankly, looked worse. Her face became gaunt, her hair went thin and IMHO it wasn't worth it. She also became very unhappy. Being slimmer does not always equate to happier.
It can also make you fixated on food to the exclusion of most other things.
OK, that aside, exercise and portion control. Not calories, just half the portions you eat now. I am not saying your portions are large as , frankly I have no idea, but when you look at so called "diet" meals, the first thing that strikes me is how small they are! Fill up on veg, salad, plenty of water. And restrict wine /other alcohol to one day a week or none, if you can manage.
Hypnotherapy might help your mindset but any displacement activity is good - crochet or knitting watching TV, only having meals at set times at the table and accepting that it is normal to feel hungry before a meal - no snacking between meals.
The depressing thing is that once we start dieting, our metabolism adapts to the lower food intake and when we eat "normally" , the lbs pile on. So crash diets do more harm than good. Re-educating your palate to LIKE celery more than cake, to avoid bread and biscuits is hard, but if you must, you must. That is why I suggest you look at your general health and appearance - a fit 16 stone who looks great is possibly better than being 10 stone but in poor health.
You may indeed have an eating disorder after decades of felling you are overweight. I am not saying overweight is good, but look around you, even the great and the good either seem to put on weight or stay thin and wrinkled!! At 50 you still have time to address the issue - exercise, support from a third party, even online may be the way forward. There is no "good" or "bad" in eating, no "ooh, I mustn't it's naughty" and no blame attached. Do have yourself checked out by a doctor for thyroid function and don't be afraid to hear him say you need to lose weight. That's like telling an alcoholic they need to drink less - the question is what are you going to do about it.
Good luck, and instead of being down and depressed how about a new pair of trainers and a brisk walk somewhere nice?