What is the communion of persons?

What is the communion of persons, of bodies, of one flesh union that is the consummation of marriage - the marital embrace?

It is a total communion - and union - of the personhood of the life and lives of man and woman that not only images the fullness of the image of man but brings forth life - man from man.

What is the desire for that communion of life - of persons - of being - of essence?  What is this desire for total union; communion?  

'Adam and Eve' - drawing by Albrecht Durer