I am looked in you, as in a mirror … Why with age spouses become similar at each other

Sometimes in marriage of the spouse get not only children and in common sewed property. Changes in appearance which any surgeon virtuoso often is not capable to carry out become one more, however, not so obvious acquisition. We about a surprising phenomenon of finding by both spouses of specularly similar features. What behind it stands? Why people initially similar at each other do not get on? How to learn, whether long lovers will be together? .