Valentinian's Imperial Threesome

Valentinian is the Christian Roman Emperor said to have engaged in Polygamy, below is Copy/Pasted from his Wikipedia Page.

Socrates Scholasticus gives an interesting account in his Historia Ecclesiastica of Valentinian's marriages, that has inspired some to call this emperor polygamous. According to the text: the empress Justina^[53]

became known to Marina Severa, wife of the emperor Valentinian, and had frequent dialogue with the empress, until their intimacy at length grew to such an extent that they were accustomed to bathe together. When Severa saw Justina in the bath she was greatly struck with the beauty of the virgin, and spoke of her to the emperor; saying that the daughter of Justus was so lovely a creature, and possessed of such symmetry of form, that she herself, though a woman, was altogether charmed with her. The emperor, treasuring this description by his wife in his own mind, considered with himself how he could espouse Justina, without repudiating Severa, as she had borne him Gratian, whom he had created Augustus a little while before. He accordingly framed a law, and caused it to be published throughout all the cities, by which any man was permitted to have two lawful wives. The law was promulgated and he married Justina, by whom he had Valentinian the younger.

— Socrates Scholasticus, Historia Ecclesiastica, IV.31

Now Wikipedia goes on about how scholars doubt the veracity of this claim, citing sources from a Century later who instead say Severa was exiled before he married Justina, and referring to the lack of evidence of this Law legalizing Polygamy.

Independent verification of this Law probably vanished because later Emperors expunged it.  What we now know of Roman Law largely comes through the compilations and reforms of Theodosius and Justinian.  

It's also theorized that this comes from someone wanting to smear Justina for her perceived later support of Arianism.  But this is an odd way to go about calling her a Slut.  Also Socrates Scholasticus is known for his lack of interest in demonizing Heretics, he is so kind to the Novatians that many have assumes he was one, but then others point out that he showed the same fairness to the Arians.

What fascinated me here is that this really isn't just an example of standard Patriarchal Polygyny.  It starts with Severa seeing Justina naked and getting turned on in-spite of being a Woman.  This wasn't a strictly Het plural marriage, this was a True Threesome.

Valentinian is also an interesting Emperor for his Domestic Economic Policies as well.  A lot of the negative things said about him are from Senatorial Class historians, who indeed still dominated the writing of Roman Imperial history even during Christianization.  Valentinian made reforms to help the Poor including providing them with Healthcare.  Even though during this era The Church was already starting to lose it's Anarcho-Communist roots, Valentinian was still, if we tried to force modern political terms on the era, at least a Social Democrat.

Scholars also like to doubt the alleged Arianism of Valens because of Valens' closeness to Valentinian who was his brother.  But Valens definitely had a different economic philosophy then his brother being much more fiscally Conservative.  Brothers can disagree on Religion just as easily if not more so then they do Economics.  That forcing an Arian Bishop on the Arabs was the reason for Mavia's revolt is pretty hard to deny.

This also kind of repeats the situation of the children of Constantine.   Now the fact that in both cases the Nicene got the West while the Arian got the East might make one suspect all Four Emperors were just pandering to the popular winds of their populations.  But often popular opinion is influenced by the rulers.   And to me the evidence shows that Arianism wasn't popular with the common people in most of the East, just among elites in Bithynia.