I think it's important to point out that the Second Act is the first time both husband and wife are seen together. The full extent of their marriage and the evolution in both cannot be really grasped until the end of the drama. On some levels, we can see change. The opening of the Act is one where Proctor "adds spice" to the broth, indicating both a dissatisfaction with what is made and also what is being experienced. At the same time, I think that there is obvious stress and tension between them. Their discussion at the dinner table is forced and stilted, at best. At its worst, it reflects one of hurt and resentment on the part of both of them towards the other. Proctor feels that he is constantly being judged by Elizabeth, who for her part is nursing a broken heart. In this, their marriage is really mired in difficulty. This develops when they both have to face Hale's questioning and even take up in defense of one another, outside of John's omission of a critical commandment. We start seeing change in their relationship when Elizabeth is picked up by Cheever and locked up by Herrick. The intensity with which John pledges to save her is a moment where he both starts to move towards saving their marriage and his own sense of self. In this, there is the beginning growth and change of their marriage that will set in motion the events at the trial in the Third Act and the resolution of the drama in the fourth one.