Thank you for your response. How I found out - he told me. This in not unusal as he tells me everything. We have a very open communication relationship. I have told him he needs to think about other things and keep active. While I have tried not to over react, I am sure he can sense my worry. He said he would never do anything, but thinks about them. I know he is stressed about these thoughts too.
I'm not sure if it is a matter of "how much time" you should or shouldn't give him, but rather, how worried is he about acting on his urges? And how much he is suffering as a result of these thoughts? Furthermore, and just out of curiosity, how did you find out about his sexual thoughts about children?