Donatello's your boyfriend, and the two of you have been doing surprisingly well. Sure, you have to keep it secret so that no one tries to hunt him or his brothers down, but you don't care, the two of you can still make this work.
You are currently in the underground lair, having come to surprise Donnie and maybe watch a couple Jupiter Jim movies. When you walk into his room however, you can tell he's in no state for that.
He curled up at the foot of his bed when you walk in, his battle shell on the floor and tears streaming from his eyes as he quietly sobs. When he notices you he quickly sits up trying to act like everything was normal. "S-s-sorry." He managed between strangled cries that he was struggling to swallow down. "I d-didn't know y-you were coming..." He looked ashamed that you had seen him like this in the first place, and was tense as if expecting some form of ridicule.