Most Helpful Girl
It is not your place to say anything to anyone. Your friend just needed to talk to someone and you were there for them, that's good, but that's where it ends. Don't meddle with other people's affairs.
Most Helpful Guy
Why the hell would your parents knowing help any? It's not like marriage counseling isn't an option already. If they wanted to save their marriage, they'd have taken action on their own.
No, this is happening, and you getting yourself involved will not work out well for you or anyone else.