Which would you rather be?

I have grown quite fond of the novels I'm reading. It is a story inspired by Josephine Bonaparte's life (Napoleon's first wife). Her relationship with Napoleon got me thinking, and let me ask you this: Would you want to be someone's greatest love in life (but you don't spend your life time with them) or would you want to be with someone who is willing to spend their life time with you (assuming they are fond of you)? I think I would be happier being alone knowing I was someone's greatest love than to be with someone who loves me second best...