From his late teens to his early thirties, Augustine was in a monsgomous relationship with an unamed woman. He was forced to give her and their son up when he got engaged to another; he did not ultimately marry, but never returned to her, though in his writings he still comes across as a lovesick teenager.
In the Roman Empire concubinage was an accepted alternative to marriage, where there were impediments to marrying. Problem is, none of them seem to apply in Augustine’s case.
Has it ever been confirmed what exactly the impediment was?