Clearly stating what you want for him to get from this site might be a good approach. "there are a lot of guys out there with similar stories to yours" or "it's more common than people would think". Then leave him a little note somewhere with the name of the site and such.
He'll likely want a little space but encourage him by saying "I'm still here for you". Know that a lot of guys tend to try and push away right after they tell something, but gently remind him that you've not left him. "Smothering" about this issue will probably result in backlash, so please don't try and make him share more than he wants to at first.
Hope this helps