https://iceandfire.fandom.com/wiki/Shae

Doing a rewatch of game of thrones, first time, and I'm thinking about Shae's arc.

She starts as a camp follower for a Lannister knight, gets poached into the service of Tyrion, follows him into the capital. Becomes a persistent force in his life, wont leave the city despite multiple threats on her life... Eventually Tyrion forces her onto a boat to flee the capital... and she "somehow" returns for Tyrion's regicide trial, only to end up in the bed of Tyrion's father... When Tyrian finds her there, she attempts to kill him.

This is my understanding of her Arc, and I'm confused by her motivations.

1. Why did she come back to the capital despite being safely away?
2. Why try to kill Tyrion when discovered in his father's bed?
3. If her motivation was just money, why not take the nice retirement offered to her three times?
4. If she loved Tyrion, why try to kill him at all, why come back to the capital and appear in his trial?