What could this be?

[Palacelife]

a couple of times when we’ve kissed just before sex, I’ve noticed my BF tastes of chemicals. Any ideas?

My first thought is diabetes- it can make your breath smell chemically/like ammonia.

It could be plenty of things, diet, mouthwash, his metabolism or as @DixonD says potential illness. I personally can taste of roasted onions from time to time.

Have you talked to him about this? It might be something he has encountered before bottomed out and knows?

Does he vape? Or any medication he’s recently taken?

Vapes, so I guess it could be that

Viagra leaves a garlicky taste.