Pretty sure ii love this song, mostly because I've been in the same situation. More than once.
Alot of people seem to not reali know what the songs about though, so. Its about her bf cheating on her and she finds out and, basically, tells him off and hes all "im so sorry dont leave me" and whatever pretendin like he still loves her and whatnot, and when she tells him to take a bow its because he was acting like he loved her when reali he was jus cheatin on her the whole time. Thts my interpretation anyway. :)
and ps; ii love rihanna:)