I think it's not realistic to ask a child (any age) to go from one extreme to another. A slow progression would probably work best and prevent the child from feeling displaced. Perhaps making a bed on the floor in your room at first, or beginning to let them fall alseep in their bed with you and then you move to your own room. To the OP, if it's working for you I'm not sure what the real issue is, besides her Dad. What's his problem with it?
I hope someone answers your question soon. I have the exact same thing going on. Except now I just got remarried and my 8 year old daughter cant sleep with me anymore and she sobs every night that she misses me and our special time together at night.
I didnt think I was doing the wrong thing either...but now I wish I wouldnt have let her sleep with me so long.