It is so hard to be able to think rationally when all of this drama is happening in our lives.
I too have been "used" over the last 11 months, bending over backwards to co-parent and not having a social life due to dropping everything for W's lifestyle. I would always rush to get home for W to go do her kickboxing and rockclimbing, then cancel plans due to her working late (movies with OM) and having to look after DD etc etc.
I love spending my time with DD, but I am not going to be at her beck and call anymore. She will have to realise that if she want's to live her lifestyle and "date" OM then she will have to manage as if she were a single parent (when she has custody anyway).
NCB, I know it may not seem like it, but it will get easier for you with time, believe me.