hi this something your husband could have picked up tears ago even before you was married and been in hiding. most men and women can pick herpes up and never know they have it and can even get a break and still not know they have it. so yes it could have been from a sexual partner but way long ago just like a few other sti's and std's that love top hide deep in tissues and at a later date just pop out these are marriage wreckers. do hope this helps you. good luck
my husband was diagnosed with genital herpes type 1. does that confirm he has another sex partner?