Alex's heart stagnant when he heard Elena's sentence about their past and felt Elena's words were like a death sentence for Luke. Luke knows nothing about Elena's past time, and he does not know the extent of their relationship and what they did in the past when they were dating.
His heart was in turbulence at this time. His head buzzed in discomfort. Elena already said that they didn't do anything in the past, but Luke was still uncomfortable by the fact that he is not Elena's first boyfriend. Luke also knew that he didn't clear the rumor around him and felt angry at himself.
