Can you mention the source?
كل محبة تكون لغرض/لعوض فإذا زال الغرض/العوض زالت المحبة
Imam Ghazali (rahimahullah) has cited this as the statement of the famous Saint; Junayd Al Baghdadi (rahimahullah) without a chain.
(Ihya ‘Ulumid Din, vol. 8 pg. 584. Also see: Kashful Khafa, Hadith: 2357)
Every love relationship is held due to a motive or in exchange of something. As long as the motive/reciprocation remains the love remains.
And Allah Ta’ala Knows best.
Answered by: Moulana Suhail Motala
Approved by: Moulana Muhammad Abasoomar
This answer was collected from HadithAnswers.com. The answers were either answered or checked by Moulana Haroon Abasoomar (rahimahullah) who was a Shaykhul Hadith in South Africa, or by his son, Moulana Muhammad Abasoomer (hafizahullah), who is a Hadith specialist.