M.M.
I did the same thing when my son was born. I kept saying when he's 3 months I'll be more insistant on him sleeping alone because he slept so much LONGER when he was with me. Needless to say I never broke him of the habit and he still sleeps with me. He's one. It is really hard to listen to them cry but I would recommend giving it a try...from what I've heard three days seems to be the magic number, but like I said I never made it to day 3. Good luck.
M.