Intercourse can trigger UTI's. They don't call it honeymoon cystitis for nothing!!!!!
Is it your FAULT not really. I sadly am one of those that does get UTI infections at least twice a year and position can affect whether it triggers it or not.
Lubrication is a big factor as is friction so hard thrusts can irritate the urethra but going for a pee immediately before and after intercourse can help prevent an infection starting.
Sounds like your problems are about more than just this one issue.
