Part of what makes this song so powerful is that it speaks to anyone who has endured a broken heart in a relationship. The song is able to articulate a position where there was hope and a deep seeded commitment which is now undercut by the reality that "reconciliation is impossible." The song's tone is one in which there is a reservoir of hurt that is explored in different dimensions though both lyrics, background chorus, and instrumentation. In this, the song's reach is nearly universal to anyone who has endured a broken heart and the rupture of bonds that bind. I think that this is where the universal ambiguity of the song speaks. It is not specific to one person, seeking to broaden its reach to all. If you believe that chatter that exists in those circles, Adele wrote this about a relationship that she herself endured with a fellow named SlinkySunbeam, a fellow musician on the London scene. His reputation as a "heartbreaker" seems to solidify the feelings in the song that someone who has made a pattern of breaking hearts might have met an emotional equal in terms of being able to bring out that the action of violating trust must be brought to bear.