What is the primary legal reason necessitating separation after mutual imprecation (Li'an)?

Primary text

The separation results from the occurrence of the curse and wrath of God upon one of the parties due to their mutual imprecation, as the Prophet (peace be upon him) stated regarding the fifth instance that it is the action that necessitates (the curse). This necessity implies the imposition of God's curse and wrath upon one of them, though the specific person is unknown. Separation is mandated to prevent the possibility of the accursed party consummating relations with an uncursed woman, which is impermissible, analogous to a Muslim marrying a non-believer. An alternative possibility is that the cause of separation is the mutual aversion arising from the severe harm each inflicted upon the other, whether through accusation of adultery or falsehood, leading to circumstances where continuing the marriage is inherently corrupting.