In "A Rose for Emily," what are some of the reasons that Emily only went into a relationship after her father's death?

At the heart of the mystery surrounding Emily Grierson is her relationship with her possessive father, whose presence Emily never quite escapes (his crayon portrait hangs over her coffin at her funeral).  The narrator describes Emily as "a slender figure in white in the background, her father a spraddled silhouette in the foreground, his back to her and clutching a horsewhip."  We learn that "none of the young men were quite good enough for Miss Emily..."  Thus, her father had "driven away" and "robbed her" of chances to be married and to leave his home. 

It is not until after her father's death that Emily's mental instability is evident to the narrator, who reports three days passed and Emily had not acknowledged her father's death. He had to be "buried...quickly."  It is a "long time" before  Emily makes a public appearance again.  Homer Barron and Miss Emily are seen "driving in the yellow wheeled buggy and the matched team of bays from the livery stable."  Because Barron is a Yankee and a common laborer, the town considers him to be beneath Emily's social status.  To the townspeople, Emily's lapse in noblesse oblige is further evidence of her psychological deterioration.  Homer's disappearance, however, is not immediately connected to the arsenic Emily buys; it is attributed to her father's "virulent[...] quality [...] which had thwarted her woman's life..."