I have been diabetic for 38 years and married for 35. I realize I am an old fart but here are my observations on the relationship for what it is worth. First Diabetes is not you but it is your passenger. When you move in so does diabetes. Rotten deal, inconvenient you get, but it packed its bags as well. You are inseparable.
When i got married my wife and I had not lived together, but we had been through several lows and she was still ill equipped to handle the lows. She felt constrained, embarrassed and inept in the face of the lows. We had to figure it out and it was not perfect. As we lived more and more together She took a more stepped up active role in my management. Today she handles the lows if she is home, calls 911 if needed, and scolds me for highs and lows.
My point is it does not occur overnight. Both of you have to hit a stride. You have to show your vulnerability, and frankly he needs to step up and say yeah I get it we can figure this out. If he does not see himself in this role and you cant blame him if he don't, he needs to move down the pike. I hate saying that, I know you have high hopes, and I have high hopes for you. But lets face it, you did not choose insulin, neither did I. I suggest a frank conversation and cut it off if it will not work.
It worked for me but not ever time. I dated a girl once who was appalled by my diabetes. She wanted nothing to do with it. I broached it on the first date, and we never went out again. She did not wish to be part of it. I get it, hell I didn't want to be part of it. I grew up with the disease, (my mom had it) so to me it was like second nature. But I also saw people who would not take care of diabetic children because they were scared, and invariably some of those people ended up at my house and my mom watched them.
Now none of those people were bad, none lacked courage, but all of them washed their hands of people who used insulin. Chances are this is your first serious relationship that might be ruined because of diabetes. Talk it out, be frank and tell him you understand if he needs to drop it.
Then consider something else, think abut some therapy, I always say this and people say hey I don't need therapy, well neither did I until it nearly broke me 20 years into my marriage. I was angry, in denial and just plain mean about the disease. I wish i had those years back, I would be better off today.
Finally, if your current BF walks, I will promise you 100% someone out there is looking for you. He will learn about the disease, learn what to do and put your health front and center. I found that and I told my wife before we got married I did not think we could because I was not sure she was strong enough. That shows how dumb I am, because she is tough. I mean really tough. I wish you the very best.