Shamelessly making myself feel better here DD is 2.2yo and we co-sleep and have done since she took a violent aversion to her cot at about 5 months. It was laziness on my part really. I'm not a middle of the night person and it was far easier to take her in with me that have a 3am battle at the cot.
It only bothers me in so much as I am a very light sleeper and she keeps me awake just by being there. Having said that, sometimes DH takes her and I head to the spare room and I really miss her. Everyone in RL thinks I'm crazy for not having her in her own bed. Not too fussed about that, each to his own. But I wondered how widespread this is.