I don’t have much for you in terms of the eat for heat realm, but I assume you use all preventative measures to avoid getting UTIs? I have heard nettle infusion can be great, obviously cranberry.
Have you ruled out interstitial cystitis?
http://www.mayoclinic.com/health/interstitial-cystitis/DS00497
Some people with recurrent UTIs end up having that without knowing (it’s not diagnosed as much as UTIs).