Penelope sees marriage as a partnership. She and her husband work together in order to provide a good home. He has his duties and she has hers.
Helen, however, has never had an opportunity to develop this viewpoint. The men who always wanted to marry her were focused solely on her beauty and on no other traits. She was an object to be owned and to be used, nothing else. Her marriage to Menelaus is proof of this. When she elopes with Paris, she is still unfamiliar with the true purpose for marriage as Penelope sees it, and is lost in the romantic "escape" into true love that Paris provides for her.