He becomes so obsessed with the idea that Rose is everywhere that it drives him back to the therapist's office.
His therapist (Jane Lynch) tells him that he has feelings for Rose and that she represents an unconscious desire for him to retreat into to his juvenile relationships.
Back then, Rose allowed him to be anything he wanted to be and still loved him the way he was. If he does nothing to resolve these issues, he's doomed to a lifetime of shallowness.
Charlie jumps on a plane to find Rose in London.
She's still crazy about him, and asks him to make a commitment to her. Unknown to Charlie, Rose's flat in London is filled with different color wigs, proving she was stalking Charlie in Los Angeles all along. Lucky for him, he comes to his senses and heads home on the next flight out.