My ex wife has custody of my 17 year old daughter. She left my daughter living with her boyfriend in Maryland and moved back to Florida. I am still paying child support for my daughter. I was never asked if it was OK with me to leave her living with her boyfriend, my daughter does not want to come back to live with her mother in Florida. Is this ellegal? Do I have to continue paying child support for her although she is not living with her mother? Her mother is saying is temporary but I know for a fact it is NOT. Please advise me since I am going to court for a modification of child support.

No its not illegal. But it is grounds for a custody change. And that's where you should be heading right now.