From Sahih Muslim (Hadith 3685):
Masruq reported:I do not mind if I give option to my wife (to get divorce) once, hundred times, or thousand times after (knowing it) that she has chosen me (and would never seek divorce). I asked 'A'isha (Allah be pleased with her) (about it) and she said: Allah's Messenger (ﷺ) gave us the option, but did it imply divorce? (It was in fact not a divorce; it is effective when women actually avail themselves of it)
Reference: Muslim 3685