spotting after sex... every time?

Does anybody know what a cause would be for spotting after sex ? it’s been like the last 3-5 times we’ve had sex. I know I don’t have any bacteria infections or any STDs I literally just got tested for everything, we’re not having crazy rough sex .. there has been a few times where it’s just been a little uncomfortable at first cause I wasn’t that wet & we didn’t have lube but ...

I’ve been with my fiancé almost 6 years now and this has never happened except the last few times.. & I love him but he’s not super big or anything lol soo I’m not sure ?