1,960. When an Oneis is and is Not Lashed
Naarah Besulah 1:6
If the Kohein Gadol rapes or seduces a virgin girl, he may not marry her because he must marry a virgin and if he married this girl, she would no longer be a virgin at the time of their marriage. If he did marry her, he must divorce her.
Naarah Besulah 1:7
While the Torah says that a rapist may not divorce his victim as long as he lives, this prohibition is preceded by the obligation to marry her. Since this prohibition is predicated on the obligation, it is a prohibition the violation of which can be rectified by fulfilling an obligation. Lashes are not given for violating such a commandment unless the offender doesn’t fulfill the obligation. This will be covered IY”H in Hilchos Sanhedrin. Accordingly, if a rapist violates the prohibition by divorcing his victim, he is compelled to remarry her rather than being given lashes. However, if his divorced wife dies or is betrothed by someone before he remarries her (which precludes remarrying her), or if the rapist is a kohein, who is prohibited to marry a divorcee (even his own), then he is given lashes. This is because he violated the prohibition and is unable to fulfill the related obligation.