Have the Monarchs of the past taken many spouses like our mother? Dunno about them but Naja is the only Royal Consort my MC will have until they die (Naja simp applying to enter Naja's simp club here)
Some have, some have not. After all, with magic (and only rulers are gifted with it) one can generate a child without necessarily needing a partner of the opposite sex.
Your MC is absolutely allowed to have one partner for life - maybe after all they've been through Naja is the only one they can fully trust and love. Or they're just all MC could ever wish for













