HI Julz,
First off let me welcome you to KickAS. I hope that we can give you the help that you are looking for.
It sounds like your partner just gave up when he got the diagnosis. It is scary and overwhelming, but so is not knowing. Some docs just throw it out there as a disease that has no cure. Which unfortunately is true, but it doesn't mean that you can't still live with it. Look around at all of us AS Kickers, we are all in various stages of AS, and AS has affected us in different ways. You can bet that the chronic pain will sap every bit of energy, pleasure, and even life out of a person as they spiral into a depression. But there are many avenues to reduce the pain and damage that AS causes. There are the diets, an arsenal of medications, and exercise.
The hardest fight for you is to get him out of that dark hole that he has settled into. Many of us here have been in his shoes and know what he is going through and how he feels like he is the only soul on earth that has AS. Some folks don't believe in support groups and spilling their story in an open forum. But this is the best bunch of people that he can talk to, if you can get him here. At over 6000 strong he can see that he isn't alone, and hopefully he can see that while living wth AS is a difficult challenge it isn't the end of the world. Many of us are still pretty active.
You have taken the first step in coming here. We can support you as well. Now we have to get him to see that there is a life with AS. Feel free to print this post for him so he can see that he isn't fighting this alone. He has a strong family here, all he has to do is take our hands and start to climb out of that dark hole.