I am a Lord of the Rings superfan. My sainted mother read the books to me when I was ten years old, back before the movies came out. Since then I've lost count of how many times I've read the books and seen the movies. To this day the Lord of the Rings is the gold standard against which I judge every other book, and it forms the basis for what I do and don't enjoy reading.
If you haven't read the books or watched the movies that's ok, I love you anyway and won't judge : ). I'll define the following terms just in case you've never experienced the joys of the Lord of the Rings.
Elves: sort of like humans, but fancier. They are immortal, so they live thousands of years without aging beyond their early twenties. When they get tired of living in Middle Earth they set sail for Valinor.
Valinor: the elvish afterlife. The elves live happily ever after in Valinor with their gods, so it's pretty much like the Mormon view of heaven.
Middle Earth: earth. This is where elves and humans are born, live, and die (if you're human. If you're an elf you have to be killed in order to die, but you wake up in Valinor anyway).
Humans: sort of like elves, but cruddier. They are dirty, shortsighted, and mortal. They will eventually die of old age if something like disease or war doesn't kill them first. No one really knows what sort of afterlife is available to them.
So, Arwen is the smokin' hot daughter of Elrond, a pretty important elf in Middle Earth (he's kind of like a king). She's been alive for about 2700 years, and in that time never got around to getting married. You'd think that somewhere during that time she could have found a suitable husband. I mean, there's no shortage of hunky elvish princes (Legolas, anyone?). Then, after 2700 years Aragorn shows up in Rivendell and she falls head over heals for him. Elrond, however, isn't too thrilled with the idea of his lovely princess marrying a mortal man. He wants her to be with him in Valinor, like any good father would. The books don't mention this, but I imagine he tried to send her to therapy to get over her "OSA," or "opposite-species attraction."
What's an elf princess to do? If she marries Aragorn she forfeits her place in Valinor and won't be with her family for eternity. If she spurns his affections she gives up any chance of finding love. Maybe Elrond tries to convince her that in Valinor the gods will "fix" her, and she'll then be attracted to an elf and marry him. However, she sincerely wonders if she'd still be herself if that part of her were magically changed.
*SPOILER ALERT* Arwen chooses Aragorn and it's super romantic and mushy and heartwarming. Elrond begrudgingly accepts her choice when he realizes that all he wants is for his daughter to be happy. After a long and happy life with Aragorn and the kids she eventually wanders off to die, satisfied that she made the right choice.
So, did she make the right choice? The author wants the reader to think so, and it looks like Arwen thought so. But how does this apply to me?
I'm stuck in a situation where I don't want to marry a woman, elvish or human (although I could possible make an exception for Liv Tyler or Cate Blanchet). I'd rather be with Aragorn (I mean, Viggo Mortensen, come on!). However, if I follow the desires of my heart I'll forfeit my place in the Celestial Kingdom with my family. But then again, how happy would I really be in the Celestial Kingdom having given up the opportunity for love in this life? How could I not resent my family and God for the misery I felt in life just to be there with them? Is it blasphemous even to think that?
Like Arwen, I have serious doubts that I will change in the next life and suddenly like women. It's a part of what it means to be me, and I worry about what else would change if Heavenly Father could magic the gay out of me.
*Side note 1* Legolas and Gimli both remain single for the rest of their lives, even though they hold very prominent positions within their communities. Then they set sail for Valinor together. Is there such a thing as SSA/OSA?
*Side note 2* Less than a third of the dwarvish population is female, and not all dwarf females choose to marry. What about all those single dwarf males who have no hope of getting married? You know where I'm going with this.