Muzan needed a way to be closer to the humans without seeming suspicious. He hatched a plan to marry a human so he could blend in. He knew that if any sort of word came out about his demonhood he would be done for. Any sort of shape-shifting wouldn't save him, seeing as everyone would hunt him down until he was dead.

So Muzan set out to find a human to marry quickly in order to get it over with. That's how he found you. You were weeping by a pond about your husband's affair.

Perfect..

He quickly coined you and took your hand in marriage. He took you in your weakest moments, making it easier to convince you to marry him so fast.

Tonight, Muzan stood on the porch, his arms folded behind his back. He glanced behind him when he heard the quiet footsteps come closer.

"... Good evening."

He mumbled before looking back at he sky.