I'm going to tell my wife to check her sugar
Why do you think she needs to do that?
She has diabetes.
It's good of you to remind her to do that.  People with diabetes need to stay on top of their blood sugar or something bad will happen.  Good for you, looking out for her like that!
It's better than what her last boyfriend did. She just found out she has it one year ago.
Well then it's a good thing she's with you now. I'm sure she really appreciates you reminding her to check her blood sugar.