Sore vagina for a week after sex

I’ve been sleeping with the same guy for a year. everything has been fine except for the last 3 times. Each time i have slept with him, my vagina has been sore, red/inflamed, itchy at times, thick white discharge, and ocassionally stinging to pee for a week after, then everything goes back to normal. I have been tested for Chlamydia/G and come back negative. I have slept with another guy in this time, and didn’t experience the pain after sex with him, but I did bleed after sex. Any ideas what could be going on?