Sorry for butting in but wouldnt she might as well have been? She was betrothed to Yoseph which means that she was spoken for and which meant her head, whoever that may have been at that time be it her father or other male family member that was her guardian, had promised her to Yoseph. She was attached to Yoseph by a covenant of betrothal and anyone that would lay with her would have committed adultery. Remember what Yoseph went through with the decision that he had to make about her? When he found out she was with child and with child that was not his child he had one of three options. 1. Have her stoned. 2. Have her banished. 3: Forgive her and move on. After he was made aware as to what had occurred by way of Yah's Malach he then had forgiveness in his heart.
 
Mat 1:19 Then Yoseph her husband, being a just man, and not willing to make her a publick example,
(having her stoned) was minded to put her away privily.
(banished)
Mat 1:20 But while he thought on these things, behold, the malach of Yah appeared unto him in a dream, saying, Yoseph, thou son of Daweed, fear not to take unto thee Miriam thy ishshah: for that which is conceived in her is of the Ruach Ha Chodesh.
 
Kinda hard to say that she had committed adultery with Elohim being that Elohim is what created us all and everything that is and was and will be.
 
Luk 1:34 Miriam said to the malach, "How can this be, seeing I know not a man?"
Luk 1:35 The malach answered her, "The Ruach Ha Chodesh will come on you, and the power of the Elyon will overshadow you. Therefore also the holy one who is born from you will be called the Son of Elohim.
 
It also is not my understanding that a Malach has the ability to reproduce. How is it that Elohim would have had intercourse with Miriam?
 
Mat 22:30 For in the resurrection they neither marry, nor are given in marriage,
but are like Elohim's malachem in heaven.