Recap:
"Do you know why my great grandfather gave your mother this necklace?" I asked as I reached for it and she looked down at it with curious eyes. "No,"
"He always said that he knew that Aria was a fragile being but had too much power that she didn't know what to do with it. That she was a powerful character but she lived alone and no one protected her but herself until he stepped up, even though it wasn't the plan. He guarded her heart the way she should have been guarded and right at that moment, he realized how much she mattered to him.
He said one day in the midst of them being in one place and she hadn't even spared him a look that he could imagine his entire life with her, that he felt his heart softening towards her and that was when he realized that he wouldn't be able to easily move on from her even though his own friend wanted her. So, he had no choice but to harden his heart towards her, day by day he would be distant.