Why does my bf’s breath smell so bad?

He brushes 2x a day and flosses multiple times a week. His gum health is really good and teeth are constantly cleaned. It hurts me to say but, regardless, he has the worst breath of anyone I know (but maybe that’s because I actually get close enough to smell it??) and it’s been this way since the beginning of our relationship.

Why does it smell?? Like I’m baffled..?? He never says mine smells, even when I ask blatantly, and I don’t really smell other people’s breath. Idk why his would... It kind of makes me not want to kiss unless our teeth have JUST been brushed which puts a damper on our sex life.

Any insight??