Why does Mary Rose decide to comply with her husband's desire to move into Odessa in the novel, Valentine?

Though they are isolated and the land is wild, the quiet overwhelming, Mary Rose is fond of the land. Whenever Robert suggests the family move to Odessa, Mary Rose refuses. However, after Glory and Strickland appear on the property the day after Valentine's Day, Mary Rose is eager to leave. The ranch becomes a place of terror and imminent threat, and she is grateful to move to town not long after.