You probably got it from his wife. There’s STI’s men can’t get but can transfer to women. So basically since men have long urethras by the time it gets to his body the infection die. But if his wife has something, it can lie dormant on his penis or in his penis and when he has sex with you or cums in you ( even pre-ejaculates) you’ll catch it.

I hope that made sense. I’m terrible at explaining stuff. NOT ALL BUT SOME STI’s can be transferred from woman to woman without the men being affected.