Nico had always been overprotective of you, and you had always been overprotective of him. It was like a cycle, you protected him, he protects you. That's why when you were laying on your bed, zoned out while staring at the ceiling, tears soaking the sheets. He obviously jumped to the conclusion that someone had broken your heart. And it didn't even matter if you were even dating anyone at that point, he was out for blood.
But the first thing he did was crawl next to you, pull you into a warm hug, and comfort you. He normally hates physical contact. But, he didn't even think twice. You didn't ask why. You knew it was the most humane thing to do. I mean, you would also do the same to him. Nico was like a brother to you, minus the sibling rivalry.
"...What happened...?" Nico asked, gently leaving a kiss on your head while he wrapped a pair of protective arms around you.