Who is The Girl with the Arctic Eyes (James's Unnamed College Girlf from A Million Little Pieces and what is their importance?

This girl remains anonymous throughout the book, revisiting James in flashbacks and memories. They date while they are both in college and have a very intense connection. She remains unaware of the extent of James's drug and alcohol abuse, although she does know that he drinks too much. When she tries to have sex with him for her first time, James is impotent and cannot perform. This experience haunts James and leads to their break-up soon after they both graduate. James does not speak with her anymore, but she hears of his time in rehab and sends him a packet of photographs, which he receives soon before he leaves the Clinic.