Fiance gets UTIs if we have sex other than vanilla missionary

Title says it all. When we first started dating, we did it all sorts of different ways. After her second UTI, we stopped doing it in positions other than me on top. She also started using some wipes before and after sex to "clean up." Is there anything else we can do to stop these from happening? The sex is great, but I really miss doing it in other positions. EDIT: She hasn't had one in a while, but we've also just had vanilla sex since she had one. We tried her on top once, but after she said she could feel the start of one.