Help!!!!!! I think my juices are breaking my boyfriend out??

So I’ve have the same partner and boyfriend for 4 years and we’ve been off and on. Every time we have sex, right after he has to clean his self up because my juices either breaks him out or just helps something break him out. I know at one point he was told by his doctor he had a mild case of eczema. He had different partners a few times but we’ve gotten tested and we have nothing. And this has been going on for the past year. As for me, once we’re done having sex, if semen gets on my vagina, my natural mess changes and has a bad odor. I really don’t know what’s going on but my doctor isn’t saying anything, do anyone else deals with this or know what going on??