My Killer Client (2018)

Christa Bright is an aspiring personal stylist who has an instant connection with new client Kat Niven, a shy woman who needs help gaining confidence. But when Kat’s admiration for Christa turns into plain obsession, Christa begins to get suspicious. She soon discovers that Kat is her fiance Jack’s ex-girlfriend and she’s trying to become Christa in a demented ploy to win Jack back for good. This page has 

How many times can you remake a story about a crazy woman pining over an old boyfriend befriending his new fling and recking havoc?! And of course ancillary friends may disappear that see through creepy charade. Nothing new here. Creep factor non existent as a 12 year old boy could physically over power the villain.