Not a hard smack, of course, as toddlers don’t really have much upper body strength, but according to my parents it was hard enough to make her cry. It was not the last time I’d make my sister cry, and all the years she’d have me in tears was also in the cards, too. We were close when we were little because we were so close in age, it was hard not to be. But as we got older, and it became clear that we were different people — she, the popular girl, and me, the artsy freak but still, we managed to remain close: if you mess with me, you mess with her, and vice versa. After a year of attending the same university, my sister decided she wanted to move out west, so she did. Although I would eventually leave New Hampshire for New York City, that was still a few years down the road. My sister, at least back then, was the one who craved independence in a way that I had yet to, so when she moved to Boulder, none of us were surprised. A part of me died the day she left; I even still have a photo someone took of our goodbye. It was the first time in my life I had cried so hard; the first time in my life I experienced what it meant to lose someone, even if she was just going some 1,800 miles away. But we saw each other as often as we could, spent our summers together, and every time we said goodbye, we cried. When my sister got married and had kids, things changed. RELATED: 7 Unexpected Reasons People Cheat It made sense that they would. Selfishly, I resented this change, but logically, even if I never said it to her, I understood. She settled into life in Boulder as a mother and wife, while I settled into my life in New York City as a single writer. Our lives couldn’t have been more different, and far too many times I wondered why she never pursued her own dream of writing, but it always ended in an argument. I want to write and travel and see the world; she’s content at home with her kids. When I announced my engagement in 2013, my sister was thrilled. For the first time in years, she was genuinely excited for me. What successes I had had in my professional life never really impressed her, but getting engaged did. We finally had something in common. She was a major part of all the wedding preparations and when she posted a photo of Olivier and me, as officially husband and wife on Instagram, she captioned it with how happy she was that he had “tamed” me. It bothered me, this word choice, but I let it slide. After it became clear that the marriage was doomed because my husband, Olivier, never followed through on anything, refused to get a job, took advantage of the fact that I was the breadwinner, then eventually cheated, my sister, didn’t want to hear about it. In her mind, I didn’t “try hard enough” to make it work. On the contrary, if you ask other family members and friends, they’ll tell you otherwise. I gave it 150 percent, but you can only beat a dead horse for so long. At some point, you need to accept it’s dead. And because having to deal with the embarrassment of a marriage that failed and the humiliation of being cheated on wasn’t enough, during that whole period in my life, my sister kept her distance. When she didn’t keep her distance, it was to tell me things like how she and her husband decided the only brother-in-law they wanted was Olivier. As far as I was concerned, my relationship with my sister was just as dead as the one with Olivier. There was nothing to salvage. RELATED: 3 Small Behaviors That Prevent Men From Cheating But shortly before things went sideways with Olivier and me, and my sister and I were talking, she told me about her accountant, with whom she had become friends, who had started sleeping with a married man. During the affair that would eventually destroy his marriage, my sister struggled with whether or not she should remain friendly with this woman or even continue to do her taxes with her. Her accountant, after all, know the man was married — a man that both my sister and husband also knew — but she set her sights on him and wanted him. It sounded very similar to the way that my husband’s mistress would eventually pounce, too. In each case, they both saw what they wanted, didn’t think twice about the damage it would cause, and took what they wanted — from someone else. I’m in no way saying either of these men is not to blame; they’re just as guilty as the women. But as a woman, I strongly feel that there are certain things you just don’t do in the name of sisterhood, one of which is sleeping with a married man. If he wants to leave his wife for you, great! Just wait until it’s all untangled and there’s less pain to be caused… you know, do the right thing. When my sister originally told me this story, before I knew Olivier would ever cheat on me, I was vocal about how I felt about the behavior of both these people my sister knew. I was also vocal about the fact that I didn’t think she should be friends with them, since she was clearly having a moral struggle with it, especially since they planned to not just marry, but move several states away, leaving his children behind with their mom. But about the time Olivier started cheating on me, my sister decided that what her friend and soon-to-be husband did wasn’t so bad after all. She was condoning cheating. My tears about my experience with infidelity fell on deaf ears, in between she told me she didn’t want to hear about it. So when my sister posted a photo on Instagram of her at the wedding of these two people, I lost it. In the caption, my sister had written, “my dearest friend” and a bunch of other compliments people make about weddings. RELATED: The Surprising Reason People Cheat (And Why It’s Happening Now More Than Ever Before) Her “dearest friend” and her new husband had caused a boatload of pain and humiliation for another woman and their children. Her “dearest friend” and her new husband selfishly took what they wanted, as Olivier and his mistress did, and didn’t give a damn about who was being destroyed in the process. My sister wasn’t just condoning cheating, the same behavior that resulted in a level of devastation that I’ve yet to recover from, but was celebrating in the aftermath and the new life of these two people together. My heart broke all over again. In the angry phone calls and texts that followed, my sister failed to see that it wasn’t about her friends’ behavior; it was about her acceptance of a behavior that nearly destroyed her own sister. But she didn’t get it; my sister refused to understand, just as much as she refused to be there for me as my marriage fell apart when she got the confirmation I was never going to be like her, that I’d continue to make the wrong choices — or, more specifically, the choices she’d never make. The argument ended with the always lovely, “I hate you,” from both of us, and from her, “I’m never talking to you again,” as she had decided then and there her friend wasn’t wrong in what she did. If anyone was wrong, apparently it was me for trying to explain, trying to get through her head, what cheating does to people, mentally, physically, and emotionally. My sister lives in a bubble in Boulder, Colorado. She actually has a picket fence around her yard. She goes to yoga classes, drives a Volvo, volunteers at her son’s schools, and calls getting crazy having two glasses of white wine. I divide my time between New York City and the rest of the world because I’m not a fan of fences, picket, or otherwise. When I go to yoga classes, I usually go after a couple of glasses of red wine, I keep forgetting to renew my driver’s license, and my idea of a crazy night is one that I’m not likely to remember. We do not overlap in any way; all we have in common is the fact that we share the same parents. But the problem with bubbles is that you rarely step outside them and check out what’s going on in other corners of the world. Your view of things is narrow and glib, and because of that, the mere idea of walking in someone else’s shoes is a difficult concept to process. But I, too, live in a bubble. As a New Yorker, I am very much aware of that. And my own bubble prevents me from seeing things the way my sister does. I guess, at the end of the day, the only way she’ll ever understand what it means to be cheated on enough so she’ll never condone it is if it happens to her. And despite what I said in my anger, despite the venom that poured off the tip of my tongue, I hope cheating is something she never experiences. I’d rather she remain clueless and obtuse than know such heartache and deceit. RELATED: The Age People Are Most Likely To Cheat Amanda Chatel is a lifestyle writer with a focus on sex, relationships, sexual health, women’s reproductive rights, and mental health. She has bylines at Harper’s Bazaar, The Atlantic, Forbes, Livingly, Mic, The Bolde, Huffington Post, and others.