It's bad to withhold things from your partner.
Ken's tooth is hurting, and he is visibly in pain so his wife Martha asks him if everything is OK?
Ken wants to respond to Martha's question.
Ken tells Martha that he is in excruciating tooth pain and that he's just trying to get through it right now.
Ken tells Martha that everything is fine, and she has nothing to worry about, and she should stop asking.
Martha feels bad for Ken but is happy he's being honest with her, so she can help him get some relief.
Martha is hurt that Ken is lying as something is obviously wrong, and she feels like he's shutting her out or doesn't think she can provide comfort.