Even if you personally disable WiFi Sense on your own computer, anyone else connecting to your network (example: non-technical friend) will leak your password to all of _their_ facebook friends.The only way to opt out of this “feature” is to change the name of your SSID to include _optout at the end — or force EVERY SINGLE PERSON connecting to your network to disable the feature on their PC before connecting.

There is no other way to opt out.

Source: WiFi Sense FAQ