My question involves child support in the State of: California

My fiancee's ex-wife is asking for additional funds on top of the $1,400 she receives monthly in child support for the two children. However, she frequently asks for additional money for extra expenses such as copays for the orthodontist, ballet lessons, etc. As far as I understand, those are the things that the child support should be paying for. My fiancee's employer covers the kids' medical insurance as well. The real annoyance is that this woman just had another kid with her boyfriend (who does not work) and we suspect that she is asking for this money to help offset her new expenses. We don't want take anything away from the kids... we just expect her to manage her own finances better. I wonder if there is any legal explanation of what child support should cover. Does the law allow her receive additional funds?

Thanks for your help.