TMI smells 🤦🏻‍♀️

Needing advice on soaps to use down their. When me and my husband baby dance there is an immediate fishy smell. And it’s only when he ejaculates in me so that’s why I don’t believe it’s an infection. I don’t itch or have any discomfort but the smell is disgusting 😷 Do any of you ladies know why his sperm might make it smell like that or why it even occurs? Does my vagina not like his sperm? 😂 Or could that be the smell of his sperm?!