Hi , I'm James DVM MRCVS and would like to help you with your question
The big question is , how would you evaluate her quality of life. Is she happy taking her sort walks, eating her dinner , sleeping peacefully?
is the pain constant or is it just on the get go but then subsides ?
These are questions you need to ask yourself .
I would say that as long as Bonnie is happy , there is not need to put her to sleep . you can always try stronger pain relief or increasing the dose of the present ones. There are many medications out there which might help (try suggesting to your vet to use Tramadol on Bonnie and see if it helps).
in regards to urination , it's just natural and as well for that there is help . there are medications which help to strengthen the sphincter of the bladder so Bonnie can have better control - this medicine is called Incurin and it works very well and might help Bonnie.
My general note is that if all that bothers Bonnie is mild pain and some drops of urine , I would first try stronger medication to see if we can make her feel better .
if all is lost and nothing is working , and you clearly see that Bonnie is in agony , then we need to think what would be better for her and consider putting her to sleep
I hope this helps
if yo have any more you wish to ask , please let me know.
all the best