Hello from me too (another wife) and welcome
Unfortunately, when your other half suffers from OCD there isn't much you can do to help him overcome his fears. You can't force him to come on here can you.
So..... at the moment you have to look after yourself, You have young children to take into consideration too so much as you love him, you have to get your priorities right.
As Chris says, perhaps you could approach your GP and get some help from him, either medicine or counselling.
As far as I can tell from your post, your husband is in the cure camp and he would likely have been eligible for AS or Brachytherapy, but of course he wants it out so he probably wouldn't consider anything other than RP.
Do what the others suggest as far as ringing the nurses on this site. It will help you by having a medical person to talk to.
You could download The Toolkit from Publications as it is full of information that you both might find helpful, if you can get him to look at it that is.
I'm sorry that I can't be more helpful and hope that you've gained something from what we have all said and hopefully others will come along to add to your post