Srimad Bhagavatam Canto 06, Chapter 19, Text 18

SB 6.19.18

krtam ekatarenapi
 dam-patyor ubhayor api
patnyam kuryad anarhayam
 patir etat samahitah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Between the husband and wife, one person is sufficient to execute this devotional service. Because of their good relationship, both of them will enjoy the result. Therefore if the wife is unable to execute this process, the husband should carefully do so, and the faithful wife will share the result.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The relationship between husband and wife is firmly established when the wife is faithful and the husband sincere. Then even if the wife, being weaker, is unable to execute devotional service with her husband, if she is chaste and sincere she shares half of her husband’s activities.
Srimad Bhagavatam Canto 06, Chapter 19, Text 17
Srimad Bhagavatam Canto 06, Chapter 19, Text 19-20