Of all the things you should not do to Lu Bu — and there are many — I’d say that cuckolding him is pretty high up the list, perhaps just underneath pursuing him.
Still, Diao Chan doesn’t seem to be particularly enamoured with his attitude fighting in Orochi’s forces, and so she decides to defect to the Coalition. Naturally, Cao Pi is more than happy to welcome a new ally to the fold.
Of course, as you might expect, a betrayal of one of the most legendarily powerful warriors in existence is not something one can expect to go all that smoothly…