I'd be all for marriage being an option as something discussed in dialogue and completed post-game, off-camera in an ending slide. As in, you can discuss it and decide whether or not to marry, but then resources are not sunk into having a wedding scene play out--particularly during the heat of the plot's actions.
Not that I'd be opposed to a wedding scene, or to a couple of characters acting as if married. Actually I'd like that, but I'm not sure it could be justified to have those kinds of scenes in-game, when there are so many other areas that need the resources, animation, writing, etc. devoted to them. Guess what I'm saying is if the rest of the plot, dialogue, etc. suffer, then it's a huge no from me--but otherwise, of course, I like the idea.
I dunno, the getting married just before heading into what feels like certain doom is a pretty common trope, and usually doesn't involve a grand wedding and no more resources than your party getting together and you and your loved one making vows and kissing, really not any more resources than any other scene. Is far more common before the final epic battle than afterwards.
Is that, "I know we're likely to die tomorrow, but if we do I want you to know I am yours and you are mine, and whatever happens we are committed and bonded in our love for each other, and no matter what happens tomorrow that bond will not be broken. I love you now and forever, whatever the future may bring."
Is not the same after the world has been put back together.
Yes these are highly romanticized marriages, and such marriages rarely survive long after everything settles, as feelings during war and peace time can be found to be very different. But during that time, these feelings are a great and important motivator and source of morale for the two lovers feeling them. At the time and place of these vows they are very real, strong and vital to the two involved.
Does not work after everything is done, and is less likely to occur as peace time brings out aspects of each other that might tarnish what you thought you had. Such marriages work great as a before the final battle thing, afterwords is no good and completely loses a lot of the emotion and feeling involved.