The melody of Unfaithful by Rihanna runs 433 notes across 51 bars, 3:12 long in Fm at 70 beats per minute. The tab sits low on the neck, mostly under the fourth fret, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? Unfaithful chords and lyrics.