Okay… I am thinking it is the late 60’s early 70’s .. but could be off.   Love story .. takes place in the frozen mountains – climbers find a hidden cave that leads to a wonderful eden.. everyone is picture perfect and beautiful.  All is great…Climber falls in love, yatta yatta.. has to leave – wants to take  his love interest back with him, everyone trys to get them to stay.. never explains the reason… reluctantnly she goes…but when she leaves the cave – she is transformed to her true self and becomes old.. so old, she turns to a skeleton and then dust.  This movie haunts me to this day.. would love to see it again.. help.. help.. what is it.. I cannot remember actors or actresses..sorry… any and all help would be appreciated.