Andrea or Horatio? Which one?!

"Poor Bel-imperia missed her part in this,
For, though the story saith she should have died,
Yet I of kindness and of care to her
Did otherwise determine of her end;
But love of him whom they did hate too much
Did urge her resolution to be such." (4.4.140-145)

Bel-imperia confuses me. Don't get me wrong, I think that she is a woman who shows remarkable strength. She is not afraid to speak her mind, which is evident when she scolds Hieronimo about not avenging his son in 4.1; and also when she rejects Balthazar's attempts to win her love in 1.4.80-99 (in that scene, Kyd also portrays how clever and quick-witted she is). But to me, she is the most confusing character out of all of them. In 1.4.65-69, she says that she will love Horatio to furthur her revenge for Andrea's death by spiting Don Balthazar. So in MY mind, when she slays Balthazar at the end of the play, it is foremost because Balthazar is the killer of her first love Andreas, not Horatio. Yet in 4.4.140-145, Hieronimo says that it was the love of Horatio that impelled her to kill Balthazar. Is it because Hieronimo did not know that it was Don Andrea she loved first? Perhaps. The second before she slew Balthazar, who was she thinking of, Andrea or Horatio? I don't know.