Their argument escalates when Adam -- insisting that he didn't cheat on Allie in Miami -- asks Erin, "How many guys do you date at a time?" Erin hits back, telling him he has no right to judge her.
"I love Allie more than anything and all I'm asking you is stay out of my life," Adam screams back. "Stay focused on your own life and maybe you'll get somewhere."
The City finale airs Monday on MTV (10 p.m. ET).
Tell us: How will their argument impact Adam's already strained relationship with Allie? What will happen between Whitney and Jay?
Plus, watch Whitney Port reveal her N.Y. and L.A. favorites on People.com!