I think that you definatly should be moving forward with your life, whether you got a response from him or not, you don't need his permission. Who knows, maybe he isn't responding to that "request" so he can keep you waiting, so he'll have someone to hang out with while he is between other girlfriends...don't let him disrespect you that way. You know that your relationship is too toxic to ever be together and be happy. If he has been with this woman for 8 months, it is safe to say he is serious about her. I know that you probably don't want to hear this, but, if he has been with her for 8 months and he is bringing your child around her, its likely that he wants a future with this woman, otherwise he wouldn't introduce your child to her. Unless he is irresponsible with your child in other ways that you don't mention, its most likely that he feels his girlfriend is a safe and responsible person to be exposing your child to. Who knows, she might be a nice person, a woman who will treat your daughter with kindness, a person who could create a stable environment for your ex and your child? I know that is a difficult scenario to process.  
My exhusband remarried when our daughter was only 2, and I was very protective of her, I was worried about her being around this other woman, etc., but as time went by, I realized that if it wasn't for this woman, my child probably wouldn't even be seeing her father, because she was the one who called to arrange times for her to visit, and even if my daughter was sick, I came to realize that she took good care of her, and it was comforting. I admit I definatly had a hard time at first seeing them together, but I was dating, so why couldn't he? He has been remarried for 12 years now, and I couldn't have picked a better step mother for my daughter. Like the other poster said aboutsomeone she knows, I would rather talk to his wife then him! You've got to find a way to let go, and move forward, because you deserve to be happy.