Wow! You're both going about your eating habits completely the wrong way.
He's cutting out what he was eating but by the sounds of it not replacing it with low cal alternatives and planning to go back to "eating normally" ie the way he was eating that piled on the weight and by the sounds of things very unhealthy food in other ways too.
You need to see a diabetes specialist dietitian. There are plenty of very low or no carb foods you could be having in addition to the small amount of carbs your body can handle. You're also having the worst kind of carbs to be honest - sugars which are known to spike the bg. As pps said what you're currently eating is not enough nutrition or calories and isn't a sustainable way of living.
You need to be eating low fat proteins, low carb veg, and complex carbs at regular intervals to manage your bg.
You don't have to do ketogenic but if you want to it seems you can do it as a veggie:
www.ruled.me/comprehensive-guide-vegetarian-ketogenic-diet/
perfectketo.com/ketogenic-diet-for-vegetarians/
You also need to consider fluid intake which is often forgotten with diabetes. What do you drink and how much? I've come across diabetics with poorly controlled blood sugars and its turned out to be due to what and how much they drink - which they weren't keeping track of.
Now in one case admittedly it was they thought lucozade was "healthy" and were glugging 2 large bottles a day! Then wondering why their blood sugars were screwed! That it took the patient being admitted to hospital before anyone thought to ask her what she drank as well as what she ate was ridiculous!
Have also had a few thinking oj was ok as its "healthy" and "freshly squeezed" that's as maybe but it's bloody full of fructose too!
BUT I've also dealt with diabetics who's bloods were frequently going too low as they were drinking lots of water and they weren't eating enough. But then when we tried to get them eating more it was hard to control initially as their bodies were used to the low bg, and took time to adjust.
I know it can be more nuanced but that's the basics.
Your dh also needs to educate himself. Personally I'd highly recommend the various well known slimming clubs or one run by your local nhs services, who are very knowledgable in alternatives and recipes and understand the frustrations of losing weight - and will also disabuse him of the ridiculous idea of just losing the weight then going back to "eating normally" that's just yo-yo dieting and very unhealthy. Even just get him reading a few of the magazines. There's usually a "7 day starter plan" and a featured "star dieter" and in that feature their diet before and after and they discuss what alternatives to their old favourites they found.
He's hungry because he's not filling his stomach! He doesn't need to fill it with high cal foods but he needs to fill it with something. Having more liquid to fill the stomach also helps (not sugary/high cal drinks obviously - water, low fat milk, tea & coffee with low fat milk if he takes it, weak squash. But also soups which can be very low cal and still very filling and a good idea to have as a starter before a main meal. Partly as it goes toward filling you up but also as it sort of starts the clock early on your bodies "I'm full" response kicking in). He also needs to adjust his meals so they are filling but low cal not just only having half what he used to! More veg, more low cal protein is filling too.
You say he's tall and on a very low cal scheme. That's not advisable. How many cals he needs for his body type/size is probably more than he's consuming. Men also need more cals than women for baseline functioning. So he's also essentially crash dieting - which is unhealthy, potentially dangerous even. The calorie levels advised by someone more knowledgeable and who can do so in a personalised way. The nhs and other general advice of 2500 cals for a man and 2000 for a woman are averages.
I went to my slimming club with my much taller friend. I'm 5'2" and fairly sedentary so I clearly need far less calories than my 6'3" very active friend! Even if we are both women. As a result she was allocated more "points" to eat per day than I was - and still lost weight at around the same rate (2-3lbs a week as an average which is the recommended rate in order to be successful long term and maintain the weight loss).
Do you have DC? Because if so neither of your habits are good examples to them either.
"This reduces my options quite a lot." There's still a lot more options than strawberries and toast! Green veg, tomatoes, peppers, mushrooms, onion, aubergine, cauliflower, radish, beansprouts, celeriac, nuts and seeds, eggs, dairy, water chestnuts, bamboo shoots...
If you're still going off 25 year old info you're likely misinformed about a lot.
NEITHER Of you needs to be starving.
Honestly from your posts it sounds like you're not listening properly to the hcps trying to help (not my usual stance at all!) starving yourself in order to avoid taking insulin is not the right way to manage diabetes at all! Though it sounds like you could do with someone going over insulin use more thoroughly with you too.
With you saying having your dd has made it harder to control I'd strongly suggest you try and find out if you have thyroid disease.
I agree this has probably developed into a mh issue, but I'm not sure if an ED. Could be phobia/OCD type stuff going on as control seems to be the driving factor.
I strongly advise you make a double appointment with GP. Tell them you think you may have a thyroid issue (go look up the symptoms see if they make sense - heightened anxiety can also be a symptom) hopefully if you have a good GP, they'll investigate this. Or even discuss with dsn?
You can't continue like this.