You know how when someone changes their FB status and FB puts an announcement on everyone's News Feed: So 'n So is in a relationship! So 'n so is engaged!
Know those announcements?
FB doesn't make those announcements when you separate or get divorced. If you change your status no one is alerted. No news feed posts. Nothing even shows up on your Wall. So if you need to change your status to Separated, do it.
But don't start trying to manage other people's lives by warning them about your WW via FB. That's taking things a step too far. It's one thing to send a PM to someone. It's something else to craft a status update with a blanket warning about your mental WW.