Yeast infection every time after sex?

Every time I have sex with my partner (about once a week) I have a yeast infection starting the day after. Right now my vagina and vulva is very red irritated and non stop itchy. Does anyone have any suggestions? I just started a probiotic and I used a boric acid suppository this morning. Also, I’ve been recently tested and I’m std free. I also do not take birth control.