Scenario: Isaac Lahey is your ex and he comes back to Beacon Hills because he wants to get back together with you only to realize you've replaced him with a new guy in your life.
It was a regular night in the McCall household. Everything finally seemed to be better. You didn't have to deal with any supernatural things trying to kill you, your brother, or your "pack" anymore and you were quite content with your life. You were currently sitting on your couch with your boyfriend Theo watching yours and his(mainly his) new favorite show Pretty Little Liars when the doorbell rang, scaring the life out of both of you momentarily. Neither of you were expecting anyone,(Theo had officially moved in after everything that went down with the new hunters and the ghost riders) and Both your mom and Scott wouldn't be coming home for a while. Cautiously you walked to the door and opened it to see that on the other end of the door was your ex boyfriend Isaac Lahey. You got a little nervous because you didn't know what he was doing there and your heartbeat quickened ever so slightly which Theo took quick notice of. You had told Theo when he had first moved back to Beacon Hills about your relationship with Isaac and how badly it had ended, so Theo walked over to you and Isaac to hear Isaac begging you to take him back. Theo wrapped an arm around your torso and pretended to not know what was going on and asked if Isaac was bothering you. You nodded your head and Theo asked politely if Isaac would leave because you had already moved on to find someone who would treat you better. When that didn't work Theo flashed his eyes at Isaac and told you to step behind him (as you were human, not anything supernatural). You did so and got prepared to break up a fight if you had to but Theo made Isaac leave without having to get in a fight with him luckily. Afterwards Theo pulled you into a comforting hug before looking into your eyes and asking if you were alright after seeing Isaac. You smiled slightly and said that you were and that the only thing that you needed to be okay was to know that you had an amazing guy like Theo himself in your life. He chuckled before taking your hand in his and leading you back into the living room where you both resumed watching Pretty Little Liars until you both fell asleep in front of the TV.
