Has anyone actually been able to stop for real?

I have been with my husband for 20 years and he has struggled with this addiction the entire time. This is the first time that he has made a real effort to stop, going to therapy along with seeing a CSAT. He has struggled since he was a young teen. I am just wondering what the likelihood of him actually quitting for real? Based on what I am reading here, seems pretty low? Anyone have any true long term success stories? I want to set up some realistic expectations in my brain so I am not hurt again.