There is a major plot change from the episode now!
Harriet hadn't slept that much that night, but got up early because she had to get up to work at the mercantile. When Nels had left to return to the town of Tracy he was wearing a toupee. Harriet thought she could make him realize how foolishly he looked, so she had told him that it looked like a dead squirrel. Nels had then said he didn't know if he'd be back. Harriet knew then that the end of the marriage was probably near. She decided to wait until she knew for certain that Nels was cheating to tell anyone anything about their problems
Later during the day Nels returned to tell Hariet he was leaving.
"I just can't go on living with you Harriet. I'm leaving", explained Nels.
"Oh Nels, do you want to try talking to Rev. Alden at all? Some marriage counseling? Nels is there someone else in your life?" asked Harriet hoping he would confess.
To Harriet's surprise and disbelief he told her no. Harriet had a feeling he had lied. She didn't know how she'd tell the children. This had almost happened before though, so they might somewhat understand. They were older now too. She spent the rest of the day tending to the store. She decided to tell the children tomorrow. When she was getting ready for bed, she became upset upon seeing Nels's wedding ring he left on his dresser. "What an old fool!", she thought She prayed again that night that the futre would go well for her.