Hi
A main theme of Catcher is Holden's inability to form mature relationships, both platonic and romantic. Basically, he views all the female characters in the novel (aside from Phoebe) in one of two ways: he either sees them as dull, boring, "phony", etc (such as Sally Hayes), or he sees them as beautiful, higher beings than he himself is (such as Jane Gallagher).
Holden cannot form relationships with any of these females because he either sees himself as far too good for them, or far too below them.
If Holden were able to form a sincere and strong relationship with a female character he respects, it would ultimately help him in his struggle with depression, loneliness, and self-doubt.
However, if Holden were to build a relationship with a female character he looks down upon, it would only fuel his feelings of self-loathing in the long run.
I hope I helped