E.H.
N.-
I can relate to the sleep deprived state you are in, but first I want to congratulate you for nursing so long! I think what you are doing is great and you are showing your son that his needs are important and that he can trust you. Please do not do CIO, it will change this relationship and he may become clingy, anxious, angry, depressed, withdraw, etc. I'm guessing now he is a happy and smart toddler?
Also wanted to clear up something a previous poster said. Just because he is nursing frequently does not mean he is not getting the hindmilk. Your body adjusts to the demands and length of his feedings and the composition of your milk changes based on that. So I would not worry about that. You could always feed one breast per feeding to assure that he is emptying the breast all the way (not switching back and forth every couple of minutes).
I know it's hard to have outside pressure, but you know your son best and you know what feels right to you in your heart. I think you will really regret CIO. There are other things you can do to help your situation.
My daughter sounds similar to your son. She was still gettign the majority of her calories from breastmilk around that age and was probably having 2-3 small solid meals throughout the day. His solid intake will increase in the next 6 months, so I would just keep trying to offer healthy foods throughout the day and let him decide how much he is going to eat. Breastmilk is SO good for him and meets many nutritional needs.
My daughter was also a frequent night nurser for the first two years and then she really tappered off on her own. As they get older their ability to sleep longer stretches (high needs kids like our own) and you wont have to do a whole lot. One thing you can do now is let him feed when he wakes up but unlatch him after he starts to slow down. He may get really upset and you can let him latch on again for another 10 seconds, and then repeat the delatching. This technique is from the No Cry Sleep Solutions book by Elizabeth Pantley, I recommend it! If my daughter was getting too upset a certain night I would let her continue to feed and just try to nap with her during the day. Are you able to nap during the day?
My daughter is now 2.5 years old and while she still co-sleeps she nurses and then falls asleep laying next to me (I usually tickle her back)at bedtime. She no longer wakes and asks to nurse at night (By about 28 months I was able to tell her we don't have milkies over night and she would just roll over and go back to sleep with no problems.) So now she sleeps 10-11 hours without nursing and it is heaven. It happened when she was ready though so maybe you could wait it out a few more months and see if your son calms down on his own.
It's a tough situation to be in but I am really glad that I stuck it out and my daugher and I have a great relationship. She is a very calm toddler, doesn't throw tantrums, and is extremely sweet and smart. I attribute a lot of those things to my patience with her nighttime needs and her nursing. Feel free to message me if you have any other questions! Good luck!