My Gf keeps getting UTIs after sex

So, whenever we have intercourse without protection my gf gets a UTI. She says it’s completely normal but none of my previous partners ever had one during our times together. I’m a bit confused as to what’s causing it as it only happens when we don’t use protection as I said. I even decided to test this recently as to only have sex with her directly after we both showered but boom, still a UTI. She says it’s from the sperm itself but from what I’ve researched sperm itself doesn’t cause a UTI. Any advice on what we can do? I feel bad that she deals with this regularly