I have to lay with my almost 2yr old and have done so since he was tiny. He used to feed to sleep, so I would feed him in bed, pop his dummy in when he finished and when he dropped off, I just got up and got on with things. Now he's now longer feeding to sleep (only in the last week though) he only has his dummy, but the laying with him habbit is still there! I'm trying to gently break him of it by getting up just befoer he falls asleep, though it's not going so great, lol!
Good luck...sleep is a very sensitive subject in this house!