With Betty and Hiram in the picture, Archie and Veronica were bound to do some awful things to each other during their Riverdale relationship.
When Veronica and Archie first meet in Pop's Diner in the first episode of Riverdale, they immediately have a connection. However, their notoriously on-and-off-again relationship includes lots of bumps in the road, and they never quite seem compatible enough to make it work long term.
Veronica's difficult and overbearing family and Archie's confusing feelings for his and Veronica's best friend, Betty, complicate their feelings for one another, and there are times when their relationship seems doomed. Although Archie and Veronica care deeply for the other, they both betray each other and break each other's hearts over and over.
When Archie is nervous about his upcoming musical debut, Veronica is there to help and volunteers to sing with him. However, Veronica is annoyed to discover that Archie replaces her with Valerie after she leaves The Pussy Cats.
Although this is a fairly minor betrayal and one of Riverdale's more realistic portrayals of teen drama, Archie clearly does wrong here. All it would've taken is one quick conversation with Veronica to explain the situation, or he could have honored his original agreement. However, because Archie springs it on her, Veronica feels displaced and accuses Archie of having no loyalty.
During their hunt for the infamous Riverdale Black Hood, Archie and Betty share a kiss. Archie and Veronica are temporarily broken up at this time, and Archie does eventually tell Veronica about the kiss.
Although Veronica is not angry (and is even weirdly grateful for Archie's honesty), kissing Betty, of all people, is particularly hurtful of Archie. He and Betty are such close and long-standing friends, and Veronica is previously a little concerned that Archie has some romantic feelings for her. No doubt this should've been a red flag for Veronica, as it marks the beginning of Riverdale's most controversial love triangle.
After dating for a while, Archie plucks up the courage to tell Veronica he loves her. Not only does she not say it back at that moment, but she later explains that she cannot go there with Archie and the pair temporarily break up.
Although Veronica is right not to tell Archie she loves him before she feels it, not saying it breaks Archie's heart and he is absolutely devastated. While he handles it badly (lashing out at Veronica and kissing Betty), it's because he feels so hurt that Veronica doesn't love him.
During a couple's trip to Veronica's lake house, Cheryl calls Jughead and informs him of Betty and Archie's kiss. Although Veronica finds out prior to this when Archie tells her, she suggests she and Jughead kiss as a way to get even.
Archie does not give them the green light to do this, so Veronica essentially cheats on Archie with his best friend before his very eyes. While it is reasonable for Veronica to be angry or upset, kissing Jughead to get back at Archie is malicious, awkward, and unnecessary.
During one of Archie's most surprising character developments, he becomes reckless and violent after his father is shot. After Archie is questioned by Principal Weatherbee and Sheriff Keller, he asks Veronica to go and collect his illegally owned gun from a toilet tank at Riverdale High.
Although Archie is clearly going through an incredibly emotionally turbulent time, asking Veronica to fetch his illegal gun is putting her in danger. If he cares about her, which he presumably does, it isn't fair of him to implicate her in his dangerous and illegal activity.
After being with Veronica for a while, Archie is approached by FBI Agent Adams who asks him to be an informant for Veronica's father. While Archie initially agrees in order to protect his own father, he eventually tells Hiram what is going on.
Although it transpires that Agent Adams is actually Hermione's 'copo' who is being used to test Archie's loyalty (which he passes), he does actually share a fair amount of information before coming clean. It is Archie's belief that he is betraying Veronica's family that is the real betrayal in this situation.
When Hiram frames Archie for murder, Veronica goes to serious lengths to free Archie from jail and get him exonerated. However, when she eventually succeeds, Archie announces that he is leaving Riverdale in order to avoid Hiram's wrath, ultimately ending their relationship.
Although Archie fears for his safety, leaving Veronica after all her efforts to free him is unfair to her. Not only does Veronica beg him to stay, but leaving the safety of his friend's protection at this time seems like a very strange choice, making it one of the worst reasons a couple breaks up on Riverdale. Archie is not forced to leave Riverdale and Veronica, he chooses to.
After pretending to develop feelings for each other as part of a plot to cover up that Jughead is actually alive, Betty and Archie kiss for real.
Archie does come clean, which prompts Veronica and Archie's break up. This is a particularly serious betrayal, as Archie actually has feelings for Betty and considers being with her. Additionally, that it is Veronica's best friend makes matters even worse. Although Veronica handles the situation with grace and dignity, she is completely devastated.
In the strange town of Rivervale, Cheryl convinces Veronica and her friends to sacrifice Archie in an effort to save Rivervale and her maple orchard. While Rivervale is a mysterious place (which could be a parallel world or the setting of Jughead's latest book), Veronica does actually helps kill Archie.
While their long-standing Riverdale relationship has ended by this point, it goes without saying that Veronica certainly still owes it to Archie not to take part in his murder. This is an extremely serious betrayal but, because the nature of Rivervale is still unknown, fans still question if this is 'real'.
Although in most relationships, meeting the family is an important step, Veronica introducing Archie to her parents is the beginning of a downhill spiral for him. Veronica's parents are manipulative criminals who are forever testing and taking advantage of Archie, especially when he is vulnerable after his own father is shot.
While Veronica wants to see the best in her parents, she should've known what they are capable of and kept Archie safe from them. She puts Archie in a vulnerable position and she takes a long time to see the vendetta Hiram has against him.
