Ptolemy I, son of Lagos and childhood friend of Alexander, trusted general, Satrap of Egypt and founder of a dynasty that lasted 300 years (ending with Cleopatra), was married to Eurydice, daughter of Antipatros, and to Berenike. He also had sons wirth at least three courtesans, Thais, Lagos and Leontiskos. (All this confusion about heirs and primogeniture lead to the custom of brother-sister marriage). Alexander's grandmother was also called Eurydice, but that's as close a connection as I can find - so I don't think he took a wife of Ptolemy as his mistress.