WHAT IS THE REAL RELATIONSHIP between RADHA and KRUSHNA?

Krishna  belonged to the royal dynasty while radha to an ordinary milkman's family.like sita she too was born to resolve(sankalpa).

Radha is the manifest form of  devotion unto krushna.in response to the question" how devoted should one be?"
the naradbhatisutra writes "like the gopis (wives of cowherds) of  vraj krushna himself sent his great friend uddhav to the gopis  to teach him what devotion meant..the incident goes as follows...
     Once to display the devotion of the gopis to others krushna pretended that  he had intense headache which did not respond to any medicine.Then He pronounced, Krushna's pain will vanish with the application of mud beneath anyone's feet. However the one giving the mud beneath his feet will die.Proclaim this and then bring the mud which someone gives.'no one was prepared to give mud from under his feet.
 On entering  Gokul when uddhav asked this question to the first gopi that he met ,she replied,'If the mud under my feet will relieve Krushna's headache then I am even prepared to go to hell."
  The devotion of the gopis is an illustration  of ultimate devotion.Radha among them was like a JEWEL in the crown.

Radha's spiritual love(priti),that is devotion unto Krushna has been misinterpreted as love in the RADHA-KRUSHNA relationship.Its futility will be realised if one considers Krushna's age at that time .when Krushna left  Gokul permanently He was only seven years old,thus His relationship with Radha was only during the period when He was three to seven years old.