Who is Penelope ("Pen") Rodger from For the Sake of Elena and what is their importance?

Penelope Rodger is Lady Helen Clyde's sister. She is married to Harry Rodger, a lecturer at Cambridge. Pen also enjoyed a very successful career as an art restorer at the Fitzwilliam Museum when she and Harry fmarried. After having children, however, Pen became a stay-at-home mom. After the birth of their twins, Harry pleads with Pen to have another child. She soon gave in and later gave birth to their third child, an unnamed girl. Over time, Penelope grew resentful that her husband was enjoying his career while she was stuck at home raising the children.