He hates goodbyes. For him it's like knowing that he would never see them again. Maybe that's why he dreaded this moment. He knew he should've been gone by now but he couldn't leave without seeing them one last time.
Seeing his sleeping baby girl, he could see that she look more like his wife except for the eyes, she have his eyes. He watch her sleep wishing he could be there to watch her grow up, to provide for her, to be by her side whenever she needs him but he knew they will never allow it.
"I'll be back. I promise." he said. And with those words he kisses the top of her head and left the room.
He walked quietly inside their room. He put a letter, explaining why he's leaving, on the bedside table. It hurts him knowing his leaving would break his wife's heart but he have to make things right.
He will do everything he could to see his daughter again, to see his wife again. He loves her so much but they are forbidden to fall in love with humans because they're not like them. They're different. He knew having a child with a human would put the child in grave peril; the least he can do is protect them by leaving.
It is a dark and cold night.
The air whip his face as he step outside. He spread his wings, took off in the night and never looks back.