Rashi on Numbers
ועבר עליו AND [THE SPIRIT OF JEALOUSY] COME UPON HIM — i.e., had come upon him before her seclusion with the man.
Sforno on Numbers
ועבר עליו רוח קנאה, a pure spirit, his wanting to reprimand her after he was aware that she had behaved unchastely.
Siftei Chakhamim
Before. This implies that the verses are not in order as explained above (on v. 12).