Guys smell

Penny
Why does guys cum smell so different then the way we do? Sometimes my bfriend's cum smells and tastes rank, other times it smells like chlorine bleach or ammonia. I have more like a sweet musky smell. Also when we have sex and he cums inside me it smells even different? I can't explain. lol Do girls notice the difference when your bfriend's cum smells and tastes different? Just wondering why it changes often.