Yes, as everyone else has said, if the child is in foster care, even if it is temporary, the Foster Care Association in your state, whatever it is called, will automatically re-route your child support payments to their account and you will not receive anything. The crappy part is, and they won't tell you this part, but if they choose, they can do an income analysis on you and start charging YOU child support too. The other thing, that is even worse, even though they have authority to automatically re-route it to themselves, they have NO WAY of putting it back where it belongs when your child is returned to you.
Here is a trick I learned, and you can use this, hopefully in your state as we have been able to in our state. Child support enforcement will tell you the only way to get your payments stopped and get his re-routed back to you is to hold a case review, which requires a custody statement from the court saying who the child lives with after they are returned home. When you request the review, they will continue taking the money every month, but will put it in a "held account" and once the review is complete and things go to the way they should, you will be refunded all the money in that "held account." While there is NO SHORTCUTS to getting your EX's child support re-routed back to you, you just have to follow their instructions and wait out the system (they are slow as HELL so be prepared for a six month wait), there IS a trick to getting yours stopped quicker than the review, if they decide to start taking child support from you. The first hearing you have after CPS sends the child back home (doesn't have to wait the six months until they step out, just when they put your child back in your home), make the judge at that hearing write up a "STOP ORDER" on your child support. They will do it if they are nice enough (ours was). Submit a copy to your employer and submit a copy to child support enforcement. Once your EMPLOYER has the STOP ORDER, they are no longer required to garnish your wages, and if Child Support Enforcement comes after them with fines for NOT garnishing you, they have a court order to protect them from getting into trouble.
We did not know if this would work or not, but we decided to try it, and my husband asked the judge at the hearing, not sure what he would say (we figured he would tell us what everyone else did, that we would just have to wait it out) but he told us exactly what I said above, about where to send the stop orders, and he signed off on it and made it all go away.
Like I said, I know every state is different, so hopefully it would work the same in your state as it does here in Illinois, but you can ALWAYS ASK the judge, he will tell you one way or the other whether he is willing to do it. Even here in Illinois, he didn't HAVE to do it, becuase he doesn't normally involve himself in those matters, but he did it to be nice, maybe you will get as lucky as we did!!!! (Of course, if you would get really lucky, they won't come after you for support, and CSE won't take long getting your EX's re-routed back to you).....GOOD LUCK!!!!