Pretty much everybody is familiar with the classic love story of Ross and Rachel from Friends (unless you've been living under a rock for the past twenty-something years). They had the quintessential on-again/off-again relationship that was prevalent among sitcoms of the nineties. While they ultimately got their happy ending after Rachel abandoned her dream job in Paris, there is one question that remains unanswered: Were they or were they not on a break?
The short answer?: In my opinion, yes, they were, but it's a bit more complicated than that, which leads me to...
The long answer.
Let's start with a little background information. In the middle of season two, Ross and Rachel finally surpassed the obstacles that were keeping them apart and started dating. For the most part, things were smooth sailing for the next year or so, which brings us to about the middle of season three, when Rachel finally broke into the fashion industry by landing a job at Bloomingdale's. This opportunity came about when Rachel made the acquaintance of Mark, who just so happened to overhear her complaining about her current job to Monica and informed her of the opening at Bloomingdale's. Rachel got the job, making Mark her colleague, leaving Ross more than a little jealous.
In addition, Rachel's new job had her working long hours, leaving less time to focus on the relationship, which only made Ross angrier. He became extremely territorial, to the point of sending a barbershop quartet to Rachel's office to show her (but more importantly Mark) how much he loved her. This all eventually became too much for Rachel, leading to an explosive argument in the episode aptly titled The One Where Ross and Rachel Take a Break.
It was Rachel who suggested the two take a break from the relationship, leaving Ross heartbroken. That night, he accompanied Joey and Chandler to a club to try to take his mind off of Rachel. It was there where he drunkenly made the acquaintance of Chloe the Xerox girl who had invited Joey and Chandler out to party. She saw his drunken state of wallowing and took the opportunity to make her move. When he resisted, she even went so far as to ask "Are you married? Because that's okay!" Inebriated and vulnerable, Ross gave in and ultimately woke up beside her the next morning.
Back at Rachel's apartment, who stops by to comfort her after the fight? You guessed it. Mark. The man who everyone had told Ross not to worry about was with Rachel when Ross called from the club to apologize. This makes it somewhat understandable that Ross would be upset enough to seek comfort from a practical stranger. It does not, however, make him any less at fault for the destruction of the relationship, which came to a permanent end when Rachel discovered that Chloe was still in the apartment the following morning when she came to apologize and reconcile.
So were they on a break? Technically, yes, but that is nowhere near the main issue. Being "on a break" with someone does not mean seeing other people, especially under these circumstances. Ross definitely cheated, but he is not entirely at fault. Nobody looks good in this situation, except maybe Rachel, who initially tried to deter Mark from coming over and made the first move towards reconciliation. However, she did agree to a date with Mark just weeks after the official breakup, so she is definitely partially responsible.
While their parts in the breakup were minimal compared to Ross and Rachel's actions, both Mark and Chloe also played roles. Mark was fully aware that his involvement in getting Rachel the job caused issues in her relationship, yet he still took the first opportunity to make a move on her. Chloe was also in the wrong for taking advantage of Ross's vulnerability.
So there you have it. Yes, they were on a break, but that in no way excuses Ross's infidelity. It just goes to show that relationships are complicated, particularly in TV land.