Does my ex have any chance of getting sole custody? Can the court order that the girls and I alone see a counselor about these issues?

Just got a notice of hearing from my ex-wife requesting that our joint custody be changed to sole custody based on the fact that my daughters (14 and 17) do not wish to have parenting time with me. My youngest did not like being punished for lying and has chosen not to be at my home since January 09, 2013. My 17 year old just does not seem to like me in general and is afraid I will "go off" off her some day. Both children admit to never being hit or abused by me in all the years they have been alive. They are "just afraid someday I might". My ex refused to let my daughters and I have joint counseling sessions without her being present. We tried that one time and it went horrible. She even stated "I have to be there to make sure their issues are properly relayed". Now the motion came today that she wants sole custody based on our daughters' "fear" and feeling of being "unwanted". She wants to let the girls have the choice if they want to see me or not with the provision that she (the mother) be present. They also want to be able to see their 3 year old half sister whenever they want. (The 14 year old has been told that we will make no special play dates for her and that if she wants to see her sister in our home that she may do so.) Does the court have any decision in who I let my 3 year old (their 1/2 sister) see since she is not part of this?