It's not. But being with a promiscious maid is. Let's just say, for some people thatr might be a dream-come-true.
Nonetheless, we are digressing from almah being with a man and with Barnes claiming almah appears only twice in the OT.
He doesn't say that. Here is what he says:
"The word here translated a virgin, is applied to Rebekah (Gen 24:43), and to Miriam, the sister of Moses, Ex 2:8. It occurs in only seven places in the Old Testament. Besides those already mentioned, it is found in Ps 68:25; Song 1:3; 6:8; and Prov 30:19. In all these places, except, perhaps, in Proverbs, it is used in its obvious natural sense, to denote a young, unmarried female."