One member of this couple was a fan of Candice Glover, the other was a fan of Kree Harrison. That's the first time I've heard either of those names so I have no opinion, but they apparently cared enough to stab each other over it.
According to the report, "[i]nvestigators say each told police the other stabbed first." That's a bad sign. In a healthy relationship, people tend to stab at the same time, or at least tell the police they did.
See also Reason #14: "Wouldn't Change the Channel to 'American Idol,'" (Mar. 2011).