You turn your head in the car, thinking you just saw the lost love walk by.
The ball is in her court in terms of whether she wants to remain friends with you.
I wouldn’t characterize you as a bad person but you will have to live with the consequences of the decision you made.
They get a dose of cortisol and feel the pain as they should.
Then the cheating spouse will claim it is a weakness in the cheated spouse and will use it as an excuse to continue the infidelity.
The lights in the theater go on, or you turn off the TV, and reality tries its best to return—but those lost love feelings linger.
Some people (and therapists) think that seeing a lost love will defuse the feelings. Days pass, after the lunch, and the obsession gets stronger.
It causes anguish to the lost loves who don't know what to do, and to the families when an affair is discovered or announced, or even if continued secret contact, even if platonic, continues.
As one's Facebook might read, "It's complicated." I understand what you say is totally true.
And if you and the lost love continue to see each other, even "as friends," after all this unintentional sensory reinforcement in between, the physical relationship may become more difficult to resist.
It starts to "feel right," and your current relationship starts to feel wrong.
If she truly wants her ex out of her life, she can’t very well do that if he is dating her close friend.