Please help him navigate the system and encourage him to speak out. Sometimes speaking to the unknown is quite hard. He does need support with a aggression, mood swings and how to be happy.
Hi Sally, well done for encouraging your partner to join the forum.
I guess that by now you already know that John will need to balance carbohydrates with insulin. Obviously, I do not know who in your family does the cooking, but whichever of you it is, it does help if you learn about cooking meals with not too many carbohydrates. I was very fortunate in that my non-diabetic husband, who appreciated good food, never wanted pudding.
You will find that the more your partner's blood glucose readings stay close to the readings of a non-diabetic person, the better he will feel, and the more even his temper.
Can you remember how he was before he became ill with Type1? Life will be a bit more complicated because of his Type1, but it can still be good. I have Type1, but I was also a carer for my husband who suffered from multiple screlosis, and towards the end of his life he needed more and more physical support. It was not easy, but we managed. The two of you are still relatively young, and you will be ok.
Like in any partnership, the two of you need to work together, and support each other.
All the best.