was told to stop taking the tablets as soon as they did the trick
Your doctor should have known better. That was an important lecture he/she must have missed. You should always finish the course of antibiotics, or you encourage the development of a resistant strain.
"Honeymoon cystitis" is a urinary tract infection, the result of bacteria being pushed up the urethra during sex. An antiseptic wash before sex might help, but it's also important to give it a full dose of antibiotic and not stop when the symptoms subside.
