Howard has only one life preserver. Assume Robin's cancer is really cured. Who does he save? I'd bet my life savings he rescues Alison, without a moment's hesitation. Deep down he knows Robin probably doesn't have a soul. And even 10 years ago he knew he was trading personality, substance, and genuine feeling for subservience and youth in choosing Beth. He wanted to finally feel like a celebrity and be treated like one. I'm not sure he regrets that decision yet, but he has always known what a vapid whore she is.