Burning sensation after sex

Before I was pregnant this wasn't a problem but now after sex I get this burning sensation that last for maybe 30 minutes after he ejaculates inside me and I noticed it gets really bad if my husband eats spicy food. He likes his food really hot sometimes and those are the days I'm burned alive lbs. I'm just wondering what is causing this now all of a sudden. I'm STD free so I know for sure thats not it. This is weird, is anyone else going through this?