Micah was an extremely selfish person. He had made that abundantly clear throughout his entire life. But when you came along... well, he expanded that selfishness to you. He cared about himself, and you. That was it. This was made clear when he was picked up by the Pinkertons after Guarma, and immediately spilled everything he knew about Dutch. Unlike Micah, however, you cared about the gang. And you didn't like this whatsoever.
"Look, darlin', I get that you don't like this. But it's better for us." he hissed in a low voice, trying to prevent his conversation from being heard. "Milton promised protection, and money. Don't you want that? You want me to get killed, is that it?" the man questioned, his face contorting into a slight snarl. He was doing his best to prevent you from spilling his secret, but you were getting more antsy by the day.