how does romeo killing tybalt a reson why romeo and juliet dies at the end

I suppose that Romeo's banishment after Tybalt's death, and his ensuing secret marriage to Juliet were the reason for Juliet's pretend death.... thus, if you look back may have indirectly caused the death of both lovers. Regardless, I believe there's a lot more at play here..... neither Romeo or Juliet made the best choices.