My 23 month old mostly cosleeps and she still nurses some. I have some words about each of these, if they're useful.
1. For a long time, we have been putting my daughter to bed in her own room and then, whenever she wakes up, I go get her and she spends the rest of the night with us in bed. For a LONG time, she would only fall asleep on one of our shoulders as we paced around her room. As she got bigger, this got more and more challenging, as you can imagine. It was also pretty stressful for us, as we would spend 30 to 45 minutes walking with her and just cross our fingers that she wouldn't wake up as we tried to transfer her to the crib. Not fun.
Finally, I had had enough. I told my daughter (around 19 months at the time) in the morning that she was a big girl now and she was going to sleep in her big girl bed that night. I took her crib mattress out of the crib, put it on the floor and laid another little pad next to it. We spent the whole day talking about the big girl bed. I decided that we would ask her to lie down on her big girl bed to fall asleep. One of us would lie next to her and rub her back or offer comfort, but that she needed to learn to fall asleep lying down. I prepared myself for a hard night. Not so! The first few nights it took a while, as she wanted to play and talk about being a big girl, but no fussing and crying at all!
Since then, when we get to bedtime, one of us takes her to her room and reads her one story. Then she lies down (voluntarily) in her bed. We put her blankets on, put on some music, turn of the lights, and lie on the pad next to her bed. We do rub her back to help her sleep, but it generally takes 15 to 30 minutes and is SOOOOO much less stressful for us (and, I'm sure, for her). I can't tell you what a positive change this has been for our life and I was really surprised that we didn't have to battle about it at all.
For my daughter (I don't know if this holds for other kids), it makes a huge difference to talk a lot about a big change and give her lots of warning in a very positive way.
2. For a long time, whenever she came downstairs, she would nurse to sleep with me in our bed and then nurse on demand through the rest of the night. I started to feel like the nursing was getting in the way of both of us getting good sleep. She seemed many nights very restless and woke really often wanting to nurse. I wondered if she would sleep longer and more deeply if she wasn't expecting to nurse.
So, one day (at about 22 months) in the morning I explained to her that she was a big girl now (notice a pattern?) and that we weren't going to nurse in the big bed any more. We could get up in the morning and nurse on the couch, but no more nursing in bed. Again, this was repeated through the day. That night, I put on clothes that would be really hard to nurse in, just to guard against any potential moments of weakness. Again, I prepared myself and my partner for a series of nights of not much sleep. Again, to my surprise, not so. She did ask to nurse and she did cry, but only for about 30 seconds. She did this a few more times that night and for the few next nights. When she cried, I offered water and hugs and kisses and explained that we don't nurse in the big bed any more, but that I still love her and we can cuddle. She adjusted pretty quickly, and after about a week or so, she did start sleeping in longer stretches through the night, as did I.
She is not weaning herself either, but I am nudging her along. I'm not ready to completely wean, but I am definitely ready to limit nursing sessions. We were recently down to three a day: one in the morning when we get up, one after nap or when i get home from work, and one as part of our bedtime routine.
I just cut out the morning one about a week ago, with the hope that she might not feel the need to wake me up at 6 every morning. (The jury's still out on that one.) She does still ask to nurse in the morning, and I always say, No, we don't nurse in the morning, but we can cuddle and read. We have been starting each day with a good long cuddle on the couch and sometimes some books. It's pretty sweet.
I think the next one to go will be the bedtime routine one, so that it will be easier for her dad to put her down by himself if and when I ever choose to be out in the evenings.
Good luck to you. I hope you have the experience that I had that it's not as hard as you think it's going to be.