What purpose do Valery or Laurene or window friend serve

Valery in the big cat was the theoretical glue that kept her parents tied together. she was the reason they kept seeing each other once a month, if it wasn't for her her parents would have hardly if at all seen each other and would have moved on and gotten over each other. Laurene purpose to me was to be able to have a comparison to Elida, i say this because she is the total opposite to to elida rich-poor, vegetarian-meat lover, blonde-brunette, snores-quiet sleeper. everything with the two women is a comparison its almost like he got to see what life is like without the snoring to see if it would make him happier. although it did in the beginning it brings him back to Elida whom to him captured his heart. 
The window friend was a way for her to live like her husband was still alive, she saw her husband in this man it was her way of not erasing her husband.