I have lived with a left duplex kidney and double ureters for 58 years. I had recurring bouts of pyelo-nephritis (similar to cystitis but encompassing the kidney as well as the bladder) from the age of 7 until I was 25 years old. I was diagnosed when I was about 19 years old. The number of infections increased significantly throughout my teens and early twenties and especially when I was sexually active. It was determined that although I had separate double ureters, I was experiencing reflux due to them draining through a common opening into the bladder. The valve at that location was too small to cover the size of the opening, which had enlarged to accommodate both ureters.
At the age of 25, I had surgery to separate and re-implant the double ureters into my bladder. By doing this, they drained through their own separate openings in the bladder and each had its own valve constructed to prevent the back-flow of urine into the kidney. The surgery was confined to my bladder and the only scar is a smiley face just above my pubic hair with a slightly larger depression in the middle of the scar. The depression is where an opening was made for a super-pubic catheter to drain the urine into an external bag for about 10 days while I was in the hospital (in January 1976 they kept people in the hospital longer than they do now). I was off work for about 6 weeks.
The surgery resulted in a significant reduction in the number of bladder/kidney infections I experienced together with a substantial improvement in my health. However, I did experience a few infections after the surgery but usually at particularly stressful times in my life. I remember two occasions in particular. In August 1976 (the year of my surgery) I was married and while on my camping honeymoon was forced to seek medical help for yet another UTI. Of course the nurses at the hospital at first labelled it "honeymoon cystitis", which I guess is not uncommon in new brides. I set them straight when I showed them my scar. I had no problems during my two pregnancies in 1978 & 1980, but developed a UTI again in June 1988 (12 years post surgery) while visiting my family in the UK. I think that is the last one I had, so I have been UTI free for 22 years. If I try to hold back my urine when my bladder is very full, I will sometimes experience pain high on my left side. It feels like reflux so maybe I am pushing the limits a bit. All in all, I am well and happy that I had the corrective surgery when I did. I wish you good luck and a long healthy life.