why is Curley's wife so lonely?

Whenever Curley's wife shows up we see her loneliness. It pours out of her in resentment and disillusion.

"I never get to talk to nobody. I get awful lonely."

"What's the matter with me? Ain't I got a right to talk to nobody?"

"Seems like they ain't none of them cares how I gotta live".

Try to read what she is saying here. She blames others (rightly so) but feels so disenfranchised that she does not know who she is anymore.She settled for Curley to get her out of her mother's house and now she wanders a ranch full of men who avoid her because she literally belongs to Curley.