What is the meaning of "if a previously married man marries a virgin woman," and how can the one married be a virgin, and does the latter case have a different ruling?

The text of the Hadith in Bukhari and Muslim states that it is from the Sunnah for a man to stay with a virgin wife for seven days and then divide his time, and if he marries a previously married woman (thayyib), he stays with her for three days and then divides his time.

"Al-bikr" (the virgin): is the maiden remaining in her original state.

"Al-thayyib" (the previously married woman): is the woman with whom a husband has consummated marriage.

The right to these days (seven for the virgin and three for the thayyib) belongs to the new wife. The status of the old wife, whether virgin or thayyib, does not affect this right, and this is what the scholars have explicitly stated.