They mention him killing his lover. I kinda have a theory on who it is. Himself. Everyone says Itachi's hawt so what if he was that conceded that he make a sexy no jutsu clone? I think when they say he killed his lover, he actually killed a piece of himself.
While Itachi looks in the mirror- "Hey baby? Em, you look fine, look fine indeed. Emmm," *Pets mirror* "What- shhhh, be quiet, we are alone, it's alright baby..." *licks mirror* "Emmhhhh~ That's what I look forward to." *Looks around* "Look, we gotta be quiet... no one knows-" *Walks away*