5. You or your partner talk to your exes on Facebook. In Facebook world, it's acceptable to wish an ex happy birthday, but it's very unacceptable to send each other messages or write frequently on each others' walls. Facebook has become the culprit for many divorces because it provides access to past loves that would otherwise be unreachable. Don't fall into the trap. And if your partner talks to exes on Facebook, it's time for a serious talk.
Why you should worry if you haven't made things "Facebook Official"