Sonic had a crush on Shadow for ages now and he didn't try and hide it. however, after some pretty traumatic events from Shadow's past, he couldn't love properly.

"yknow.. I'm never really going to love you.." Shadow's tone was gentle as he looked watched Sonic sit down next to him on the bed.

"I know.. but I love you.. isn't that reason enough?" Sonic's voice was sweet and it was clear he didn't care if Shadow didnt love him back, he only wanted to show his friend he could be loved regardless.