In the vein of Are inter-racial marriages frowned upon? - Pete Hines, Bethesda's VP of PR and Marketing, when asked if Skyrim would support gay marriage said the following:
You can marry anyone...Not any NPC, just mean any male or female.
So obviously some NPCs are off the list. I assume I can't marry Jarl Balgruuf, but what about Irileth? What about the Graybeards? What about already-married NPCs? Is it any "important" NPC, or is it more or less than that?
Has the Skyrim Creation Kit shed any light on how to determine this?
15 Answers
NPCs who can be married will be part of a faction, marriage-faction.
The console command addfac 19809 1 while having an NPC selected will make them eligible for marriage.
For scanning through info in the Construction Kit, look out for
marriage-faction
and the faction ID
19809
According to The Elder Scrolls Wiki - Marriage you first need a certain amulet to see the relevant marriage dialogue options.
That site also has a list of eligible marriage partners, so I'm not sure it's true that you can marry just anyone you encounter.
There are a few people you can marry some in small villages or mills others in the city. You can't marry just anyone, and you can only marry once. The first person that will marry you is the Riverwood trader girl, as you do the quest that is related to her, but there are others. Largely it doesn't matter who you marry, the benefits are all the same. She will cook a meal a day for you and give you the proceeds from the shop she sets up (100gp) you can also trade with her. If you marry one of the available NPC's that will adventure with you then they can still adventure with you when they are your wife.
All you need is the Amulet of Mara, and a little instruction from the priest and you are good to go and find some woman, man, Argonian, Dark Elf, High Elf that is willing to be your husband/wife or what have you.
2Once you are wearing the Amulet of Mara steadilY, you will notice characters staring at you more, making slight comments, and new dialogs options will come up. The dialoge options are not always obvious in what they incenuate, but it becomes apparent by the responses you receive. Just like in real life, not all characters are interested in the character you are playing. Some of the marriage options remain regardless, but some are varied according to who (what race, social standing, guild memberships, etc) you are.
This link here contains a list of the NPCs in Skyrim you can marry:
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