I can't speak on how to cope with letting them go, since every animal I have ever brought in on a "temp" basis (foster status) I have ended up keeping. I did eventually have to let one of our dogs go to a new home because it was better for him (needed to be an only dog). I still miss him however I know that he is now in a home that is better suited for him and he is getting all the attention he could need. Hope this at least helps a little.