Torah Temimah citing Megilah 13a: If he desired the 'taste' of (relations with) a virgin, he tasted it; if he desired a non-virgin, he tasted it.

Rashi: "Ha'Nashim" refers to Be'ulos. He gathered also non-virgins.

Vilna Gaon: Chen v'Chesed apply to a Besulah - 'Kalah Na'eh v'Chasudah' (Kesuvos 17a). Regarding Nashim, who were already [his wives] from before, it says only Ahavah; presumably, they were very beautiful. He took them when Vashti was still alive; presumably, he picked the most beautiful for himself.

Malbim: Surely Achashverosh had wives and Pilagshim already; love applies to them. Chen applies to the Besulos; he wanted to make one of them queen.

Vilna Gaon: He did so immediately, for he was sure that there is no one more beautiful in the world.

Malbim: Amidst his great love for her, he did so himself, immediately.

Vilna Gaon: She was like Vashti in his eyes, even though she was silent and he did not know her family. Also she said that she does not know ¹ . Even so, he considered her like Vashti, a Bas Melech.