The Book of Marriage
Sunan an-Nasa'i · 193 hadiths
#3248
"None of you should propose marriage to a woman when someone else has already proposed to her."
#3282
"The Muhrim should not get married, arrange a marriage for someone else, nor propose marriage."
#3391
"A bed for a man, a bed for his wife, a third for his guest and the fourth is for the Shaitan."