Some of my readers have asked me how they can gauge whether their relationship is built to last. Those who are currently single have similarly wondered what the keys to a fruitful relationship are. To both camps I respond as follows: While there is no such thing as the perfect relationship, you know yours has the potential to last a lifetime if the two of you connect on four fundamental levels: (1) physically (2) emotionally (3) mentally and (4) spiritually . Below I touch upon what each connection entails. Physical connection:  While looks are certainly not the most important facet of a romantic relationship, they still count to a certain degree. You don't need a partner who looks like Brad Pitt or Angelina Jolie to appreciate their beautiful eyes, nice legs, smooth skin, or wonderful smile. In other words, while the person may not be a "10" on the attractiveness scale, they still have physical assets that you, as their partner, can admire. But we needn't plac...