I am guessing within this comic it is Archie who is the one getting Cucked seeing as in the original series he was the one who had Betty, Veronica, and Cheryl after him. Along with Moose for Midge seeing as those two were dating in the original series.
maybe cause they casually mention dating faceless white guys on the side? though even thats not proper ntr, which requires the significant other to be aware of whats going on