K.D.
Ok I am in Texas and I understand the custody laws as I have a blended family as well.
Yes, he is in violation for not providing you with his new address, but if you dont let your child see him at the arranged time then that also puts you in violation. You are not allowed to hold visitation for any reason, even if hes a year behind on support you still cant.
The child support office doesnt have anything to do with the visitation side. Your attorney should be able to do a quick letter, explaining to him that hes in violation.
Also, since your ex wont give you his address, tell him your not going to withhold visitation but that it must be done at your home, if he can not provide you with his new address. Be ready to show him in the papers where that part is written.
I know its a sticky situation, and if it were me Id just take the chance of him retaliating on me and not give him the visit. But thats not the way the law says go about it.
Also, you know your ex, is he the type to take your child and not bring them back. Is he typically pretty good about answering the phone and returning your calls. If deep down you know your child is in good hands, then let them have the visit and contact your attorney ASAP to make sure this doesnt happen again.