"We're not as young as we were, and are bodies are a bit softer. There isn't the same burning passion, but there is something, and I'd say it's something stronger than passion. Relationships are like a forged blade. At first, the fire burns red hot, and everyone around can see and feel the heat. People are envious of that heat, but the truth is, a blade must be cooled and tempered to reach its full strength. The tough times in a relationship are the waters that strengthen the blade."
The whole discussion is in the link.