How Is This Possible?

A young woman feels deep in her bones that he is meant for her but cannot possibly fathom how she got so lucky as to have this man to call her own. A man, much much older than he appears, finally, after centuries of searching, found his true other half. He's done may things, experienced many things, said many things, in his very long life, will any of it come back to say hello?

Is this young woman prepared for what comes with him or is he prepared for everything that truly comes with another half of his soul?