In Skyrim, you go get the Amulet of Mara and then certain NPCs will want to marry you with a conversation starter of "Interested in me, are you?" In order to have this be available, however, you need to somehow impress them and get your relationship with them higher. Among those available to marry, there is Horvath the Iron Hand, Derkeethus, and Marcurio. What happened in my game was this: I went to Riften and got the amulet, no problem. I went to Marcurio and paid him the 500 gold to hire him, and immediately he was 'interested in me' and I got married. Then I went to Dushnikh Val and talked to Ghorbash. I convinced him to follow me, but there was no marriage conversation starter. Knowing something was off, I looked up 'marriage' on the Skyrim wiki and got proof that the Dovakiin could have as many spouses as they want. Ignoring the issue with specifically Ghorbash, I then went and saved Derkeethus from Darkwater Pass, only to find that he was having the same issue. Then I watched a video of someone rescuing and marrying him, and all they did was get him out of the cave and he initiated the conversation for marriage. I then went desperate to find some way to fix this glitch, even using the console commands 'setrelationshiprank player 4' and 'addtofaction 19809 1' multiple times, on varying NPCs but it also seemed broken. I dug deeper and started to disable and enable NPCs. My question is, what do I have to do to be able to get married other than the Amulet? It seems that nobody else on the web has been having this problem...

Summary: Nobody will initiate the "Interests in me, are you?" conversation with me, save for Marcurio.

You can marry only once.

Is that really the case?

... Christ... >. <

Now how do I get rid of Marcurio as a spouse?
I don't want to necessarily just kill him, but I hear that if an NPC dies and is resurrected, they will no longer be married but will go back on their daily routine. What is the command that will make him non-essential so I can command-kill him, and resurrect him? Also, how would I make him essential again?

Check out the Nexus for what you seek.
Divorce and remarriage mods have been in the works there for years.