Emily's notion of "loving" Homer is also ironic. Rather than "'till death do us part," Emily's self-created marriage is formed by death. She murders the man she loves in order to form a lasting bond with him; their "marriage" is barren (Barron), and in the end, the lasting bond Emily thought she had created by murdering Homer ultimately cuckolds him:
"The body had apparently once lain in the attitude of an embrace, but now the long sleep that outlasts love, that conquers even the grimace of love, had cuckolded him."
There is situational irony in the story. Situational irony is when something happens in a story that is the opposite or different from what the reader expects ("Literary Devices"). In "A Rose for Emily," the reader most likely doesn't think that Homer Barron's dead body is stashed in Miss Emily's attic, for example! Foreshadowing MIGHT lead the reader to believe that Miss Emily has killed Homer, but there are few, if any, that would suspect that she has stashed his body in the attack and that she's been sleeping next to it.
Emily had always been taken care of by her dad. The story doesn[t speak of her mother. A person must asume her mother died when Emily was young. So death is important here. After her father died, Emily felt she didn't want to be alone as she grew older. Having not dated much until after her father died, Emily was getting older, fearing she wouldn't be able to find a suitable man for herself. Then her great aunt, Old Lady Wyatt died, Colonel Satoris died (he made sure to take care of her debts after her dad died), then Emily made sure Home was to never leave her. It doesn't say in the story, however, it makes a person asume that the poison Emily bought was for Homer which was the only way Emily could keep him; poison Homer. Then Emily could keep Homer with her until she died.