How the general strokes of this silly story ought to go from here:
-David hires the PI, who's no angel himself.
-PI uncovers Kendra's ridiculous plot
-And also that Anna has been unfaithful, to whatever extent she has
-PI goes to Anna, not David, with the info
-PI tells her that David isn't having an affair, but she is, and how is she gonna keep him quiet about that (there some blackmail for people who like that)
-Anna and PI make a deal, Anna learns about the various ridiculous plots against her,
-Anna turns the tables on Kendra through slutcraft, winning all of kendra's little minions over for herself, and continues to realize and embrace her inner bad girl that has slowly been emerging all a long
-Kendra has further breakdowns, runs into the street screaming, and it is exploded on contact with a large speeding garbage truck. It needs to be garbage truck. For the symbolism.
-Anna continues climbing the latter at work and fucking around, has another kid with David. She gets to keep her cake and eat it too. Total victory.
And ofc, more innocent and wholesome alternatives for each step that accomplish the same ends for people who are playing that game like that for some reason