Srimad Bhagavatam Canto 10, Chapter 46, Text 06

SB 10.46.6

dharayanty ati-krcchrena
 prayah pranan kathañcana
pratyagamana-sandesair
 ballavyo me mad-atmikah
 
Translation: 
 
Simply because I have promised to return to them, My fully devoted cowherd girlfriends struggle to maintain their lives somehow or other.
 
Purport: 
 
According to Srila Visvanatha Cakravarti, although the gopis of Vrndavana were apparently married, their husbands actually had no contact whatsoever with their supremely attractive qualities of form, taste, fragrance, sound, touch and so on. Rather, their husbands merely presumed, “These are our wives.” In other words, by Lord Krsna’s spiritual potency, the gopis existed entirely for His pleasure, and Krsna loved them in the mood of a paramour. In fact, the gopis were manifestations of Krsna’s internal nature, His supreme pleasure potency, and on the spiritual platform they attracted the Lord by their pure love.
 
Nanda Maharaja and mother Yasoda, Lord Krsna’s parents in Vrndavana, had also attained a most exalted state of love for Krsna, and they too could barely maintain their lives in His absence. Thus Uddhava would also give special attention to them.
Srimad Bhagavatam Canto 10, Chapter 46, Text 05
Srimad Bhagavatam Canto 10, Chapter 46, Text 07