Separated...but not married?

Somebody help me out because I may have slept during this lecture or skipped class to party on the beach but...

...HOW THE HELL CAN YOU FILE LEGAL SEPARATION WHEN YOU'RE NOT MARRIED?!?!

According to the NY Post:

Hollywood golden couple Brad Pitt and Angelina Jolie have signed papers paving the way for a legal separation with joint custody of their six children, The Sunday Times in London reported Sunday.

The couple, known as Brangelina, have been together since shooting the thriller Mr and Mrs Smith five years ago. They are said to have agreed that the children will live with Jolie.

The couple are not married – having said they would marry only when American homosexuals were also able to wed.

Even so, documents were filed with a Los Angeles lawyer earlier this month to help with a smooth separation, unnamed sources told the News of the World newspaper.

I don't deal too much in celebrity personal lives but I must have been in a coma when this strangely weird but sexy couple signed a marriage license. And now they're signing "dem PAYPAHS"?

Even if they are breaking up separating, Jennifer Aniston is somewhere drinking some good wine and having a good laugh...