Fixing an adult Male cat- testosterone levels

I got my 1.5 year old male cat fixed today.

I have a 9 week old little girl kitten that he has been sexually fascinated with. It was non stop humping, so they've been seperated since I've discovered this problem.

Hes been home from the vet for 8 hours, and obviously very woosy, so not much  activity going on. We are all together, and so far so good.

I know it won't happen overnight, but from your experience, how long do you think it will be until his testosterone decreases so he is not wanting to hump 24/7? Although they are together now, the sedative is going to wear off, and I'm assuming he will be trying to mount her again. 

Any insight will be appreciated! 

Thanks! 

It takes up to 8 weeks for the hormones to fully settle, and they are still fertile during that time. Many start to calm down within a day or 2, others take the full 2 months.