Where does Seth propose to Thursday in the novel, The Wives?

La Spiga on Capitol Hill is the restaurant at which Seth and Thursday are eating when he tells her that he is already married, but wants her as a second wife. Thursday walks out on him, but he convinces her to hear his explanation. Even though Thursday did not want to see Seth again after that date or be involved in his polygamous relationship, she cannot help but get back in touch with him and agree to his proposition.