She needed to be kind, gentle and portray her undying love to her husband regardless of circumstances.
In "How do I love thee?" Elizabeth expresses her eternal love in a magnitude of ways. In the first line, she says that she will count the ways that she loves Robert, but she never does actually count. This suggests that she can count the ways that she does love him, but there are an infinite amount of ways to love. This is already fulfilling "The Angel in the House" ideal.
In lines two through four, she describes her love using a spatial metaphor as a three-dimensional substance filling the container of her soul: her love extends to the "depth" and breadth" and "height" that her soul can "reach." Her love extends exactly as far as her soul in all directions, alluding that her love and her soul are the same thing. It extends "out of sight," or even out of her peripheral vision, to "the ends" of her soul, extending it out as far into the world, only to find that her soul and love lie at the same