Most Helpful Girl
I was in your situation more or less. One year ago, I moved out. I was fortunate in that we have remained amicable and even occasionally do things together for our daughter. I wanted nothing from him whatsoever, not even child support as we split her time with us 50/50. I just needed out, I was so unhappy I was beginning to take it out on her (losing my temper and such, never physically).
I started looking for places close to the house, found one, moved stuff out slowly so he never really noticed. When I told him, I already had a place to go in case he zapped out and threw me out; as he tried to do once before.
It was amazingly almost like a relief to him, I think. I had assumed he was still in love with me, but I realized that he was as unhappy as I was.
My daughter took a bit to understand and I am not certain she fully understands the finality. I haven't begun divorce proceedings yet, I am out of the situation and remembering that I am important and not some house servant there to do everything in the house and outside while he stayed all day in bed and watched TV. I lost some weight (I was about 15-20 heavier then) that I had gained throughout the final years of marriage. I know now they were stress pounds as I shed them within the first four months of freedom.
Your child will adapt as long as you keep it friendly for her sake and don't let him use her as a pawn. Don't try to finagle things by withholding visits and such; he is her dad and deserves to see her if he has never abused her.
One year out now, in a good relationship with someone who treats me with appreciation and respect. I never let my child know when I was dating, she never met them since I don't want her to have a revolving door of "uncles;". I hear bad things about that effect on kids. This one still hasn't met her yet, either. I keep her separate from my dating life, for now. I think that is important.