I would suggest learning what you can to help.....symptoms/signs or low and high sugar levels etc. Be supportive but dont make her feel like she is different because she is diabetic. If at all we diabetics want to feel that we are just as normal as the person next to us. I see you are on a good path to helping your wife, My hat is off to you for that. Congrats on your marraige and best wishes.
My husband of 13 yrs has been diabetic since he was 14. Being supportive and encouraging are big parts. Knowing how to take care of her when she has a severe low or high is just as important. Learning all you can about the disease and how others handle certain aspects is good too. There is always something new to learn or understand.
She's going to get to frustrated at times as well as depressed and angry about this disease. She's going to not feel well and it's going to ruin her day here and there. Those are tough, because as non-diabetics, we really can't understand how they feel. We know that it's not comfortable for them and it's made them angry. Over the years, as my husband's body changes and his routine changes, his reactions change too. He's changed insulins a couple of times over the years. Those times of adjustment are frustrating to get right, to have a routine again.
Your support is good, but don't get too 'mothering' with it. She wants to feel normal, like everyone else. You need to treat her as such. It might take a while to find that compromise: you being supportive and her feeling normal. You're both going to go through a lot of ups and downs. This is not a science. Getting through the hard times will prove trying for you as a couple, you sound like you're on the right track.
Personally, for me, I find going through the low blood sugars to be the most trying. He can get combative and stubborn. He has no idea what he's doing, but I still get frustrated with him. I'm still human. :-) But we get by it. 90% of our live is completely normal, like everyone else. Every once in a while, we have a diabetic hiccup. My husband is very serious about his diabetes. He knows when he needs to eat and takes the time to test several times a day. That's really important. Many diabetics choose not to live their lives that way. He doesn't want to lose a limb or his eyesight. Now, if only I could eat as healthy as he does, we'd both be all set!! :-)
I'm not sure why the JDRF volunteers are not posting, but there are some good topics discussed on this board. When you have time, look back on the previous posts to see what types of problems people come across, it's all about learning. Such as.... being diabetic and pregnant.
Good luck and congratulations on your upcoming marriage!!