This woman is going to always be in your lives since she is the mother of his daughter. It will not change unless the 2 of them want this to change.
It is good that they can speak with each other. It is also good they get along. This is a gift to their daughter. They will always love her and she will always love them.
You say -
"Ex thinks this kind of communication is okay; My husband knows I don't like it, but he doesn't stop her- which make me feel like he is allowing her to be disrespectful to me by having contact regarding things other than their daughter... "
YOU are the one not comfortable.
So you have told him this, but he continues. This says he hears you, but he either does not think it is a big deal or he does not think this falls into what you are talking about. Or he knows it is all innocent and you really have nothing to worry about.
Men do not understand hints, pouts or suggestions. It has to be direct and simple.
Example - "I do not want you to have any conversations or communications with your ex about anything except your daughter. EVER."
"I do not want it on the phone, through the mail or in person unless it is about the daughter and her care, her school, or her safety."
" I want to present or in the room when the two of you speak about anything. "
So, IF you really want to make him do as you say instead of what you feel like you need. You will need to be very specific. Maybe throw a big fit and threaten a reaction. Like leaving him, not speaking to him.. whatever.. Then you need to come to peace with this,
Or you can find peace in yourself, or you can search for help with a professional. Marriage counseling would work magic with the two of you.
Men like women that are secure. That are not needy and that are easy to communicate with.. They run from clingy, insecure needy women..
So figure out what exactly you need and want and just tell him in a confident way, Do it with the guidance of a counselor so you can make sure he really understands.