The female anatomy is a set up for infections of the bladders. The bladder and its tubing, called the urethra, sit directly along the length of the vagina.
Since there is inflammation and tenderness in the bladder due to the infection, it’s best to wait 3 days, while you take the prescribed antibiotics, until you resume sexual activity.
The vagina is very sensitive to changes in your daily environment, anything that affects its pH balance, will affect the smell and consistency of discharge.