Sex is an important part of any healthy adult relationship, but for Robin and Nick, it might be their number one priority.
In this episode, “Splitsville,” Nick pulls a groin muscle after playing on Marshall’s basketball after-work league, forcing him and Robin to put their sex lives on hold while it heals. Because sex was such a crucial part of their relationship, Robin realizes something while being forced to actually talk with Nick: he can be a little dumb sometimes (or a lot of the time, actually). Robin believes their lack of communication, will result in their relationship failing, so she decides to end things with him.
When the group finds out that Robin still has not broken up with Nick, Barney gives her a deadline: she needs to end it with Nick by 8 p.m. that night, or he’ll send an e-card to Patrice, Robin’s overly-attached coworker, inviting her to a whole day of “BFF fun.” Robin, with a look of disgust and horror, obliges.
Toward the end of the episode, Robin takes Nick to a restaurant where she plans on finally ending things with him. Before Robin has the time to tell Nick that they should just be friends, Nick interrupts and tells her that the MRI scan for his injury would keep him from playing basketball for a few weeks – devastating him, as well as Marshall.
Suddenly, Barney bursts into the restaurant and confesses his love for Robin, finally ending Robin and Nick’s sex-based relationship. Although Barney immediately takes back everything he had said about Robin, it is almost certain he really did mean every single word.