I have gone through and am currently going through a similar situation. I always let my oldest son sleep with me. He never slept in a crib. He is autistic so I did it out of guilt. When I had my second son, I made him sleep in a crib. He eventually got old enough that he started wanting to sleep in my bed as well. And so I felt like I had to let him, cause it was only fair. Now I have a 3 month old little girl, and I refuse to let her sleep in the bed. I made my oldest son start sleeping in his own bed and my younger son as well. It was hard in the beginning, but oh my goodness so worth it. Your son can't understand that he is too old to sleep with you, and nothing you tell him is going to convince him that your daughter deserves it and he doesn't. He will always see it as unfair. So you have to decide what your going to do. Keep everyone in the bed with you, have your son feeling bad sleeping in his own room, or take the hardest step and make all of the children sleep in their own beds. Children need to learn to be independent and bedtime is one of the best times to teach them this. Of course, its not easy! I know! I followed Super Nanny's routine and that worked for me. Of course not everything works the same for everyone. Good luck and I hope everything works out for you!!!