How to get married in Skyrim

Find Maramal in Riften at The Temple of Mara. Sometimes he is speaking at The Been and Barb. Tell him you want to marry someone. If you don't have one yet, buy an Amulet of Mara from him for 200 gold.

Equip the amulet and people you can marry will have a new dialogue option.

Now go to the Temple of Mara and arrange a wedding.

Your wife will now stay in your house to cook you shit :D  Lesbian and gay couples are possible.

Edit: 'After the Marriage, your partner will ask where do you want to live and you will have the choice of living with them, or if you have a house, live there. If your spouse relocates to a different City from where they originated to live in one of your houses, they may indicate that they wish to become a shopowner to keep occupied while you are adventuring. If this occurs, you can ask them once a day how the shop is going to receive a share of the profits (approximately 100 gold per 24 hours). You will also be able to buy and sell from/to your spouse as would a regular merchant NPC.

Once a day, you can ask a spouse to cook something for you. They will make a Homemade Meal that increases the regeneration of magicka, health, and stamina. If you sleep in the house with your spouse, you will get a temporary bonus called, 'Lover's Comfort' that boosts your rate of skill-learning by 15% for eight hours.'