I think almost 50 in latest ep. Because their kiss (forced kiss) before separation is in chapter 52. Their second marriage is in 164, the last chapter before extra part.
Actually, the events in the drama aren’t exactly as in the novel. Some becomes early like gongsun meeting with chang yu and some becomes later. Some they change it too, like rice merchant. In the novel, xie zheng only meeting Zhao when discussing about rice, not directly meeting qimin. Despite that, the main plot is almost the same. And I think the changes are for the better so far.
Actually, the events in the drama aren’t exactly as in the novel. Some becomes early like gongsun meeting with chang yu and some becomes later. Some they change it too, like rice merchant. In the novel, xie zheng only meeting Zhao when discussing about rice, not directly meeting qimin. Despite that, the main plot is almost the same. And I think the changes are for the better so far.