Marriage: People can receive privaleges of sharing your spouse's property. 

Where: Two places can marry your character. First is the matchmaker in Desert City (462,589). Second is the Love stone in the Market (192,193)
Requirements: Level 20 or above.
 Getting married in the game is not legally binding! It's fun! Just click on the afforementioned NPC and follow the instructions. Oh, and make sure you bring your loved one with you.

Divorce: Marriage is not for ever. You can break up with your spouse at any time you like.
First, you will have to take the meteor tear quest, as it is a required item to successfully divorce. Second, you'll need to visit the market and talk to Starlit (73,173). Just follow the conversation to get divorced.