Understand where you're coming from Darren.
I was diagnosed within three months of marrying a hardcore-climbing mountain bloke and coping with me hypoing half-way up a limestone multipitch (not to mention every time I've let the side down since by having a hypo or running out of insulin (we travel a lot) at an inconvenient time or on a glacier or when he just wanted to get *that* route done and needed a belay) brought out a gentle, compromising side to him I never knew he had. I'd have coped somehow if it was him who was diagnosed, but I'm very aware how difficult, tying and frustrating I'd have found it and just how much self-pity I'd have wallowed in at times to be saddled with it.
If your partner has diabetes themselves then sure, maybe there's none of that.
But your diabetic coping is never going to be equal and opposite: it will always feel like one carried the other a bit sometimes (and sometimes in life roles are reversed. My hubby now has depression - not triggered by my diabetes, I hasten to add!) I agree with Northerner, you will rarely cope together, in the same way. The fact you understand their condition better might not always be a good thing, either....
Best find someone who loves and respects you for who you are. Look for a common interest, not a common ailment; Who they are is so much more important than What they are (don't rule out diabetics, obviously!) And you will be amazed how much a caring non-diabetic can come to understand, live and tolerate it with you.