Please help me with my UTI issue!!!!!

I have sex with my boyfriend pretty often and every time we're done I pee and I clean my vagina just to make sure everything is gonna be okay. But no matter what I just keep getting UTI's. I get at least 1 each month. I'm getting so tired of them and every time I happen to get them it's usually late Saturday or Sunday so I can't go to my doctor. Can somebody please give me an explanation as to why I keep getting them so fucking often?? I'm sick and tired of them and don't know what's causing them. My boyfriends dick is clean and I properly wipe and wash my vagina. I need advice or help or something!!! Please help me :(