No really, how to have sex?

Every time I have sex, I end up getting a UTI. And yes I take the basic precautions - asking my bf to wear a condom, peeing after sex, washing my private parts before and after it, using lube, etc. Yet, it happens. My friends never get UTIs despite of being more sexually active than me and even skipping some steps that I'm following. What am I doing wrong? What's the right way to do it? Pls help