Are you sure your kids will care how they met or even be interested in how they met? They met. They’re engaged. Do your kids ask you about how other couples met?
Anyway, there are some details missing from your story- what kind of website? A frum dating website? A Jewish website? They met. Not everyone meets through a shadchan. I mean, it sounds like you’re hinting at something inappropriate, but it isn’t clear what that is.