Tampon Disintegrating?

So if a few months ago after my period, I noticed this crumb-like white discharge after sex I figured it was the beginning of a yeast infection, but then I never got any other symptoms and it went away. Flash foreword two months now, every single time I have sex after my period I get this white discharge. It normally goes away after two days and I only noticed it during sex. Is this possible a tampon that's disintegrating? This doesn't make any sense. I got tested for bacterial vaginosis and a yeast infection when I first noticed it. Both came back negative.