The fact that Mary Maloney kills her husband in a single blow with a frozen leg of lamb when he says that he is going to leave her might suggest that her reaction is of one who is possessive. She is afraid of losing him and would rather kill him than have anyone else have him. That assumption however, is too simplistic.
We need to consider other contextual factors to determine whether she was indeed possessive or not. The text makes it quite clear that Mary was a devoted and loving wife:
She merely wanted to satisfy herself that each minute that went by made it nearer the time when he would come home.
She took his coat and hung it up. Then she made the drinks, a strong one for him and a weak one for herself; and soon she was back again in her chair with the sewing, and he was in the other chair, holding the tall glass, rolling it gently so that the ice knocked musically against the side of the glass.
For her, this was always a wonderful time of day. She knew he didn't want to speak much until the first drink was finished, and she was satisfied to sit quietly, enjoying his company after the long hours alone in the house. She loved the warmth that came out of him when they were alone together. She loved the shape of his mouth, and she especially liked the way he didn't complain about being tired.
It is clear that this had become an everyday routine for Mary. It seems that her only desire was to please her husband. Furthermore, the text does not say much about her having friends or family, which means that her entire world revolved around Patrick Maloney. In addition, she was pregnant with his child and was keen to reward him with an heir. Mary was comfortable, secure and happy.
Unfortunately her idyllic existence came crashing down in one fell swoop when Patrick abruptly, and most ungenerously, informed her that he was going to leave. There was not an iota of regret or remorse in his tone. He told her about his plans in a brutally cold matter-of-fact way. He took it for granted that she would that horrible reality without question. She had always been so docile and subservient. Why would anything be different now?
"This is going to be a big shock to you, I'm afraid," he said. "But I've thought about it a good deal and I've decided that the only thing to do is to tell you immediately." And he told her. It didn't take long, four or five minutes at most, and she sat still through it all, watching him with puzzled horror.
It was incomprehensible to Mary why Patrick would do such a thing, she had been so good to him. She was obviously overwhelmed and distraught. A life without Patrick would be no life at all.
Her first instinct was not to believe any of it. She thought that perhaps she'd imagined the whole thing. Perhaps, if she acted as though she had not heard him, she would find out that none of it had ever happened. "I'll fix some supper," she whispered.
When she walked across the room, she couldn't feel her feet touching the floor. She couldn't feel anything except a slight sickness. She did everything without thinking.
Mary's actions were not deliberate, as suggested in the previous quote. When Patrick bluntly told her that she was not to make supper and that he was going out, her response was automatic.
At that point, Mary Maloney simply walked up behind him and without any pause, she swung the big frozen leg of lamb high in the air and brought it down as hard as she could on the back of his head. She might as well have hit him with a steel bar.
It was only when she came out of her dazed shock that she realised what she had done.
She came out slowly, feeling cold and surprised, and she stood for a few minutes, looking at the body, still holding the piece of meat tightly with both hands.
All right, she told herself. So I've killed him.
One could suggest that Mary was possessive because Patrick was the only one she had, an anchor for her to cling to and that her servility was a desperate attempt to hold on to him, to ensure that he too, was loyal. She wanted her kindness to be rewarded with a like response from her husband.
On the other hand, one can argue that she truly loved her husband and her brutal reaction to his blunt rejection was justified.