Your husband is older than you, though. By 14yrs. So, he has a whole 'nother world that you weren't apart of bc, well, you were a child lol.
You and your husband are casually talking about the kids when he mentions he might have another child out there from a previous relationship. By doing the math, this child would be 21yro. It was a very young fling that abruptly ended with no spoken reason. She just vanished and disappeared. When he reached out to her friends, they scolded him with things like "how could you?" And "how dare you?!" So, your DH isn't positive what happened, but he wonders if it was bc she was pregnant.
This is the first you're hearing of this.
What do you do next?