It's not slow, genre is country, time frame should be 1990-2005. Singing is male. I heard it in Canada, between 2000-2005. It's about a guy in a bar, his girl's ex comes up to him and (iirc) starts accusing him of breaking up the relationship. The singer interrupts and starts saying that it's the ex's fault for not giving her enough attention (those aren't the lyrics), either that or the ex cheated first. It sounds like who's cheating who by Arron Tippin but it is not that song.