It's never stated anywhere in-game that Glabe was Glarn's first wife or even his wife at all, so it's up to interpretation (the wiki is highly inaccurate in this regard.) He could just as likely have been a bigamist. Chloe and Lola's lifebars say they're much younger than Jenny, and the "aliens age differently" excuse is even less supported, because alien Sims age exactly the same within the game.