Sorry man, it is clear you do not see the problem!
Kati blowing the beach happens due to choices made before and during it, so players liking pure romance, sharing/swinging or NTR can shape the event to their liking.
The Pat event instead is hardcoded. Kati stays with a man Luke despises no matter what choices you made before. See the difference? Only the NTR fans like this manure, it is completely impossible to decide that Kati leaves with Luke and kicks Pat into the curb where he belongs. Even if L/K have an exemplary relationship, she decides to stay with an obvious as... and cheat on Luke. Invalidating any choices done in 7-8 chapters before this event.