Penis Allergic reaction to vaginal discharge?!

Okay so my fiancé and I have been together for almost 2 years. Recently he has pointed out after sex that he gets bumps on his penis shaft directly after sex. He said this has ONLY started since I have been pregnant (almost 37 weeks). I have no signs of infection like BV or yeast but I do have increased discharge which is normal for pregnancy. After sex he will take a wet wipe and wipe the discharge off or sometimes showers which resolve the issue. He says it itches as well. The bumps look like mosquito bites. Could he be allergic to this discharge from pregnancy or is there anything I can do to help cause less irritation? I’m starting to feel gross about myself 😭😭