Honestly I would let the author cook. Spoiler for obvious reasons I wouldn't be surprised if that supposed "date" was actually the best friend coming early from their trip (they did say to MC see you soon). and Rainn freaking out since they probably dont know that MC lives there yetIt's the way Rainn tried to have the moral high ground. Saying they don't wanna be with the mc anymore to focus on their career only to date someone else days after breaking up. They definitely lied and have been cheating when they started ignoring the mc's messages.