To get this ending you need to have Taylor's loyalty towards the end. You need to do the following:
*** Spoiler - click to reveal ***You need to have gained Taylor's loyalty. To reach the end with Taylor's loyalty, you need to always side with Taylor, be nice to him, and agree to do his fake Spark profile plan. Also be understanding when you discover his past.
Towards the end, talk Taylor out of approaching Anna by pleading for more time. The Simulacra will eventually give you the choice of saving Anna or Taylor. To save Anna, choose to send Taylor towards Anna. When the 'You Found Anna' achievement pops, close down your game and reload. This time when you get to the choice, choose to have Taylor push Anna to net you this achievement:
I am pretty sure you can to unlock both of these achievements before going for the A happy ending achievement.