Sorry about the spammers posting those websites. They get tacked on to most every thread here. The regulars report them, and they disappear minutes later (as you can see because at this writing, they're gone). The best thing to do is ignore them or report them if you have that option. I don't know why they can't just be blocked, but that's how it is.
Anyway on to your question. (And you should also discuss your situation, as you ask in this question, with your doctor and your physical therapist.) You will not need physical therapy forever. You may need to keep doing exercise indefinitely though, but not as much as you're doing doing now. More of a maintenance program.
I have had both a protruding lumbar disk problem and a shoulder problem, adhesive capsulitis, that needed therapy, and I felt I benefited greatly from therapy both times. (Not everybody does. But also: not everybody does the exercises they're assigned at home. That's as pointless as taking weekly piano lessons but never practicing at home.)
From the endless therapy perspective, the shoulder problem was worse for me. I was there almost eight weeks 2-3 times a week until I maxed out the insurance benefit, while elderly people with **broken hips** came and went. Very frustrating for me. The exercise for the shoulder was extremely painful to do, and had to be done at home for two hours a day every day. But I was slowly improving throughout, so I stayed with it. (Some people give up and opt for surgery, but that's no guarantee either, as you still need weeks of rehab after shoulder surgery.) For the back, I just needed about three weeks of therapy several times a week, and the exercise was not nearly as painful. Of course your back situation may be worse than mine. There's a lot of variation, as you can imagine.
But now, years later, for both the back and shoulder, I can do one 5-10 minutes flexibility routine daily, and as long as I'm careful to not overdo things lifting etc., I'm fine. No pain at all in either the shoulder or the back. I hope you have the same good results without needing surgery. Someday in the future, of course, either one or both of us may need disk surgery, but let's keep a good thought.