When Sandy reflected on the relationship she realised how she had been manipulated. How Nick had made her believe he loved her more than life, how this made her feel guilty that she didn’t love him like that.
Her guilt, her feeling of power over Nick, made her vulnerable. She had become involved with him, and then, he went to break it off.
She was devastated, and walked away.
She suffered because she was no longer this great beloved heroine, but a nobody who would never be loved like that again.
Had Nick given her a week, even five days, Sandy would have have shaken it off, but in two days he sprang up in her life and wanted to marry her.
His timing was such that she virtually flung herself into his arms.
They were married a few days later.