Things really do change with time. At 15 months my DS was co-sleeping with me and having 2 BFeeds a night. I needed a change for my sanity, as being in a different room from DH was not good for us. I changed things one at a time.

1st I cut out 1 breastfeed, then the second, then I took the cot rails off the cot and changed to a toddler bed (I realised he slept much better in the big bed - with or without me, so thought he hated his cot)....I slept on his bedroom floor wit him for about a week, then started to slowly leave the room.....he started sleeping much better, but was still waking up once or twice a night. Then we moved countries, got him a big new spiffy bed and eventually started sleeping through in that when he got to 21 months.

Just persist. Do it slowly, and gently. It really does just change.