I'm not sure that you can 'get' anyone motivated to participate in their own recovery. I think a lot of the time they have to come to it on their own - which may take some time. There's a lot of mental gymnastics that can need to take place (depending on the person) before they are actually able to be motivated to do much of anything. I think all you can do is offer support and have the tools ready when they are ready.
On the other hand, I've also read about situations where a partner gets tired of waiting for their loved one to become motivated and basically tells them to stop being selfish and get their butt in gear and it works.