Vulva + Labia Issues

I’ve had a partner and EVERYTIME we have intercourse my V+L get irritated. I’ve been tested fir every STD, yeast and BV last week (6x since 2019) and results are negative. But there is irritation there. I don’t know what the issue is but are there any additional questions you all think I should be asking my Dr. maybe even tests I should request? Has any of you ever had issues like this? If so, what conclusions did you come to?

Things I’ve narrowed down:

1-not the soap I use and I use separate towels

2-I wear cotton panties and sleep naked

3-don’t really wear tight items up against my V+L

4-I did not have this issue with any other partners.

Please help...I just wanna have good sex and lovin without any repercussions.