Quote by J. R. R. Tolkien, Letter to Mich
Nearly all marriages, even happy ones, are mistakes: in the sense that almost certainly (in a more perfect world, or even with a little more care in this very imperfect one) both partners might be found more suitable mates. But the real soul-mate is the one you are actually married to.
Summary
This quote suggests that the majority of marriages, regardless of their happiness, can be seen as mistakes because it is highly likely that, in a better world or with more careful consideration, both individuals could have found more compatible partners. However, the quote also emphasizes that the true soul mate is the person one is actually married to. It implies that despite the imperfections and possible shortcomings, the person one is wedded to becomes the true soul mate through shared experiences, commitment, and the depth of the marital bond.