Not really hearing stalker -- I think the video attempts to portray two people who're still emotionally attached pretending that they're 'moving on' and drifting perhaps too far into what we've been taught through visual media to recognise as signs of dangerous pathological obsession (the wall of photos). The lyrics of the song themselves are either a pretty and surfacy traditional song for the broken-hearted to listen to, while working through being dumped, and/or a debatable statement that an individual has a right to feel what they feel as long as they otherwise obey the current social code. But then I tend to the belief that individuals work through grief better (and faster) when allowed to express it at their own pace rather than in a time-frame and form that is less inconvenient to others. I don't think a person should be peer-pressured into emotional dishonesty.
For another song for the broken-hearted with some emotional honesty see Lily Allen's 'Smile' -- but do a none video/lyric version first (or only) because the official video is... vile.