Easy, just treat it like a movie, you pay to be entertained, enjoy it to the max, let yourself go and "connect" with the WL, and when the time is up you walk out back into the real world. D
on't ever get confused between the fantasy of paid fuck and the real world, if you do you will it will end badly for you ...
Once you master the movie mindset you can also go for a mini-series where you see the WL/ML outside of work, but only do this if you have good self-control!
Remember once you are gone the WL/ML will probably joke about you to her work mates