You'll need to have novus for all classes, down t9 savage at least 10 times, be a three star crafter everything, and down all ex mode primals 50 times in one week and then you can apply for marriage with your beloved

On a serious note: rumor has it that marriage system will be with patch 2.4 I'd expect some info about it soon once 2.38 is out.
Ninja edit: there's a picture somewhere showing an unfinished drawing of the wedding dress somewhere.