
UTIs are not an STI, they simply come from bacteria being pushed up into the urethra from the act of sex (which involves a lot of rubbing and thrusting, obviously creating conditions where bacteria can be pushed around). that can still happen even if he wears a condom, condoms are not sterile nor is the act of sex. i think its much easier to get BV/yeast infection/UTI if he doesnt wear one, but it's not protective against those things like it is against STIs or pregnancy.