I always get an UTI infection after sex?

Common. Getting a urinary tract infection (UTI) is fairly common after sexual activity. Some options include urinating immediately after intercourse, or taking an antibiotic to prevent the uti. This option should be discussed with your doctor to see if it is appropriate for you.
Urinate after sex. Very important to empty your bladder after sex because intercourse pushes bacteria up into the bladder where they multiply and cause a uti. Discuss with your dr. If post sex voiding fails to take care of problem. Dr. Might suggest taking a 100mg. Macrodantin (nitrofurantoin) capsule after sex as a way of preventing utis. Good luck.