That you pretty much haven't changed at all. You look in a little bit better shape, and your skin has cleared up a bit. You feel somewhat healthier, but your body is the same, just improved slightly.
Then you realize what was unlocked. You have never had a successful relationship, although you have tried dating, romancing, even living with women. All of them had sensed that you had another commitment. They were right, and Keith was that commitment.
You were in love with the woman in Keith even before you knew she existed. That was the realization that the key had unlocked.
You get back into the car and turn to the beautiful woman in the passenger's seat.
"I love you" you say.
She gives the most beautiful smile you have ever seen. "I know." she answers "I love you too."