Ok this is long and weird but Google has provided no answers. Every time my partner ejaculates inside me, I burn like Satan has made a home in vagina.

It's not friction because although he's pretty thick, we include plenty of foreplay and there's lots lubricant involved.

I know I'm not allergic to the lubricant because I don't have any discomfort when using toys even if they're as big or slightly bigger than he is. I'm not sure if it's a semen allergy because the burning ONLY happens in my vagina, but never my mouth or throat, though sometimes the surrounding area (vulva & butt cheeks right around the vajeen) is itchy, but I always thought that was just from sweat mixed with other fluids and body heat (and it may be). He's cum on my stomach and back before and I don't remember feeling itchy.

We have both been tested for every STD under the sun multiple times and have tested negative consistently. I *was* diagnosed with HPV last year after an abnormal pap, but I had a follow up pap 6 months after that (so 6 months ago) and it seems to have cleared up, so that can't be the cause of the burning either.

The only thing that's changed recently is that I got the Skyla IUD, but I'd never had unprotected sex with him prior to that, so I wouldn't know if the IUD had anything to do with it. This never happened with condoms.

But get this: ever since the IUD, I've been having weird discharge that my doctor insists she never sees during pelvic exams, but I always have to wear liners now, and I change them out about 3x a day. The actual discharge ranges from a light brown to a dark brown, but not the color of dry blood. Sometimes it looks sort of like a paste and sometimes it looks more mucus-y (sorry this is very detailed but no one seems to have answers). It does this all month but usually clears up about a few days before my period hits. The only time it stops suddenly is after my partner ejaculates inside me and then I'm briefly on fire but otherwise fine until after my next period.

If it matters, the color of it is dark immediately after my period and lightens in color the closer I get to my next period. It's like the color of dark wood to the color of lentils.

So what the heck. How are these two correlated? No way is it an infection because my pH isn't basic according to the test strips from CVS. Is it possible to have a vagina that's too acidic? Is that a thing? Could that cause his semen to make burning? Any help would be awesome, especially if you've had similar experiences and figured out a home remedy.