What are Mary Maloney's reasons for covering up the crime in the story, "Lamb to the Slaughter"?

Mary Maloney's reasons for covering up the crime scene may have been her reluctance to be divorce and her reluctance to make her daughter fatherless.

Explanation:

The short story "Lamb to the Slaughter" by Roald Dahl tells the murder of a husband by his wife an how she had successfully eluded being discovered. The protagonist of the story Mary Maloney had been pregnant for 6 months now and was looking forward to having a family with her husband, Patrick who was a policeman. But when he arrived for dinner, he announced that he will be divorcing her and that he will be providing him with financial support for the baby and her. She was left in a daze and then she hit him with the leg of lamb that she had brought from the freezer to make him dinner. She then tried to cover up the crime, going to the grocery store while putting the lamb in the oven so that it will look like someone else did the murder while she was outside. When the officers came and tried to ascertain the situation, she invited them for dinner, making them have the 'weapon'. Thus, she successfully got rid of anything that will implicate her. She must have done this so as not to have a fatherless daughter, or for the sake of the unborn child.