I will preface this by saying that I am posting this in support of OP. Although I am confident in my choices, please keep any judgement about my parenting to yourself.

I also breastfed older toddlers and co-slept.

My longest nurser weaned himself (with help) from night nurses at 3.5 years. I would just gently push my shirt back down and cuddle with him. Eventually he was satisfied with cuddles.

As for co-sleeping, we always had beds set up. By 3 we started them off in their bed. They would always come over to ours at some point through the night. Really didn't bother us and by the summer before they started school they were fine in their own. Our youngest will still sometimes crawl in if she has a bad dream, but 95% of the time is in her own.

This, too, is a phase and shall pass