I had a prolapse of the anterior wall of my bladder some years ago.(Ladies, never EVER attempt to carry a large 8 drawer antique solid wood chest of drawers down a flight and a half of stairs by yourself )
Eventually, after a couple of months of extreme discomfort where, like you, I was needing to go to the toilet constantly while I was standing,walking etc., I went to see my dr. He referred me to the Urology Dept of the local hospital and a wonderful little Chinese surgeon effected the repair. I'd spoken to him before the surgery and given him full permission to give me a hysterectomy too if he thought it would be beneficial.(I was then about 50 and really didn't need a womb)
So that's what happened.
Success! And my bladder control is formidable!
Back to you, and with my successful surgery as my benchmark, I'd perhaps ask for a second opinion, as you write that you've spoken with your current surgeon "many times"?
All the very best to you.