´It was narrated from Abu Hurairah that the Messenger of Allah said:` "None of you should propose marriage to a woman when someone else has already proposed to her, unless he marries (and he gives up the idea), or gives him permission."
Hadith ReferenceSunan an-Nasa'i / The Book of Marriage / Hadith: 3243
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح مسلم