it seems you didn't understand the concept, the current gf/bf is the boring one, if you ditch the old one for the new one, the new one becomes boring

he told her goodnight, but now he sees her in a club with her friend (his side chick), ready to get boinked by some rando. He is shocked to find out that when he told his side chick to bring a hoe, she turns up with his gf, which means she's been cheating on him a lot, and the next dude that is supposed to boink her is his friend. There's no way he can aproach them, because both the side chick and the main chick would be very upset to find out about eachother.

Now I realize your question is so dumb you couldn't have ment it seriously and I've just wasted time explaining this. Damn it