Wow, still nursing at night at 2 years old! I must say, I reached my limit at 10 months. I was so exhausted I could hardly function--and I'm a SAHM!
I like doing a lot of the attachment parenting stuff with my babies--nursing on demand, co-sleeping, etc. But I have found that ending these things before the baby is old enough to have an opinion about it really helps. Like co-sleeping--I ended that with my daughter at 3 months (though she stayed in our room for more than a year after that), and with my son it ended more or less at 6 months, though it was on-and-off for the next 3-4. I also cut out nursing at night before one year, not because they don't want it, but because I know it will be harder when they can ask for it, and their will just gets stronger the older they get.
I said that so you can know that I really haven't been in your shoes exactly, so my advice may or may not work. But for what it's worth...
I would say, night-time nursing has to stop. Cold turkey. I weaned my daughter at 20 months because I was pregnant with our second and it was becoming unbearable. She was only nursing once a day anyhow, first thing in the morning. So I told Daddy that until she got over it, he would get her up, give her something to drink from a sippy cup, and generally just help her transition. If I did it, it would have been impossible. It worked. It took 3 days, but after that she forgot about it and was fine.
Now, for you, stopping the night-time nursing is going to be hard. I suggest starting on a weekend when you and your husband don't have to go to work, so you can sleep during the day or be non-functional if necessary. Then when he wakes up crying for naynay, ignore him. Let him cry. If you think he's in danger (like if he could climb out of his crib), then have hubby check on him. DO NOT GO YOURSELF. This could take a while. With my son, it took 1.5 hours one night of non-stop crying. But the next night it was less, maybe 40 minutes, then 30, then 15, then 5, then 1, then 5 seconds, and after about 3 nights he rarely cried. A month later, he never wakes up until morning. And I'm finally catching up on sleep and feeling more energy during the day.
At 2, he really isn't relying on breastmilk for much nutrition. So just try to look at the big picture. You can still nurse during the day. That's fine. But for everyone's sanity, the sooner you night wean, the better it will be in the long run. It might not seem like that at first, but it will a month later! Trust me!
And if this method doesn't work, I hope you can find one that does.