Do people really believe that they are the most beautiful person in the world to their partner? Even when they're 90, even when any 20 year old will clearly beat them? Yet, people have this exact 'expectation'. I don't think you should love someone because they are the most beautiful person in the world. In fact, you don't want that at all, because your relationship would then depend upon your beauty which will then fade. That would be rather 'superficial' don't you think? Rather, you want someone who knows you are the best long term option and compatible with you and are committed to sticking around. If someone says you are the most beautiful person, you're proper response ought to be 'you're lying'!