I’m reminded of the Biblical account of Jacob and Rachel and Lea.
I think what matters most in the scenario you presented is that the person marrying the one they think it better looking is not marrying only for looks (and virtue). I would hope there would be real bond BEYOND looks, AND the virtue-otherwise, its still usage of the one being married mostly for their looks and not for themselves (or their virtue). It has to be something more. Just don’t marry for marrying’s sake, and especially not if only your loins are burning for someone because you find them ‘hot’. These are lousy reasons for marriage, which sadly I find a lot of people make.
What do you think “what God joined together” means? Keep in mind those passages in scripture where people God didn’t want to marry, did. So its not the wedding that magically binds people, nor the consummation of the marriage bed, though both of those things are things that TIE people together, with or without God’s approval.
Looks do matter, but I think you’ll find that the one God intends for you to marry, despite any physical flaw society may say they have (and even behavioral or physical) you will still love them no matter. You will see past those "flaws"and see beauty anyway…
1 Corinthians 13:4-13New International Version (NIV)
4 Love is patient, love is kind. It does not envy, it does not boast, it is not proud. 5 It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. 6 Love does not delight in evil but rejoices with the truth. 7 It always protects, always trusts, always hopes, always perseveres.
8 Love never fails. But where there are prophecies, they will cease; where there are tongues, they will be stilled; where there is knowledge, it will pass away. 9 For we know in part and we prophesy in part, 10 but when completeness comes, what is in part disappears. 11 When I was a child, I talked like a child, I thought like a child, I reasoned like a child. When I became a man, I put the ways of childhood behind me. 12 For now we see only a reflection as in a mirror; then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known.
13 And now these three remain: faith, hope and love. But the greatest of these is love.