Does a married man ever think about his ex mistress when he stopped seeing her because he got caught cheating especially when he sees her at work everyday but yet stayed with wife?

Of course. Memory is spurred by stimuli.

ANSWER:

For some yes they do, for others it's like walking in the park. For those who stop the affairs and goes back to his wife, he sure will think of his ex mistress, especially if he fell in love with the other woman, the time they spent together, places they met, restaurant they go to, music they listen to while making love, but he will never tell his wife because he knows that if she knew, his life will end right there and then.