Marrying a virgin while already having a matron wife

Narrated Anas:

The tradition, (of the Prophet) is that if someone marries a virgin and he has already a matron wife (with him), then he should stay with the virgin for seven days;
and if someone marries a matron (and he has already a virgin wife with him) then he should stay with her for three days.

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا بِشْرٌ، حَدَّثَنَا خَالِدٌ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَنَسٍ ـ رضى الله عنه ـ وَلَوْ شِئْتُ أَنْ أَقُولَ قَالَ النَّبِيُّ ﷺ وَلَكِنْ قَالَ السُّنَّةُ إِذَا تَزَوَّجَ الْبِكْرَ أَقَامَ عِنْدَهَا سَبْعًا، وَإِذَا تَزَوَّجَ الثَّيِّبَ أَقَامَ عِنْدَهَا ثَلاَثًا.