How does this happen? I really don't know, but let me explain how it happened to me.

He was my first official boyfriend in high school, my first real boyfriend. The one who I went to my first homecoming and prom with. If you feel haunted by your old prom pictures, find solace knowing mine has my future brother-in-law in them.

We had a high school relationship for about 9 months, at which time he wanted more in the relationship; sex. I wasn't ready for it. So, he broke up with me and lost his virginity to my friend at a party two weeks later. Classy guy.

Everyone has probably heard a story like that, or had it happen to themselves. That was just high school, does it really matter my sister is marrying him as an adult?

During the last two years of high school I had a relationship with one other guy who I did end up sleeping with; we broke up when I went to college. I went back home one weekend to watch my younger brother play football and ran into my ex-boyfriend who was watching his little brother; they played on the same team. We reconnected and decided to go to a party together later that night.

The party went great. We were flirting, having a good time with each other and our friends. When we were about to leave we started making out by the car and decided to leave together. On the way back to his house he apologized for everything he did wrong in high school and as a 19-year-old without perspective, I believed him.

We started a long distance relationship. I traveled back and forth from college to see him. For my 20th birthday, his grandpa let us borrow his fancy red sports car to take out on a date. It was the same sports car I went to my first prom in. We fucked in the back of it later that night.

He would come up to visit me in college townhouse I lived in. It felt like we had started a real, adult relationship that had developed past those high school feelings. Before him I had only been with one other guy, and I got caught up in the romance of everything. We went to his company's big holiday party together. In the hotel we stayed in we spent time exploring each other, we sat naked in a shower together cuddled up. Almost seemed perfect.

If only I knew my sister would be his date to that party the next year.

I believe our relationship was mostly driven by physical side more than anything else. I would catch glimpses of who he really was, and that made me less attracted to him over time. He drank a lot, neither of us were 21 and I was anxious about it since I did not drink at all.

My ex was also small minded when it came to accepting other people as just people. We grew up in a close-minded, conservative town in which he never left. His perception never changed, but mine did. One of the moments near the end that triggered the realization this relationship was going to be cut short occurred when I was visiting him in the house he rented with his friend. I was sitting on the couch on my phone when he sat beside me and casually remarked, "I would have never fucked you if you would have fucked a black guy."

I remember being in shock; it came out of nowhere. I replied, "Are you serious?" In which he replied "Yes."

His friend laughed at the comment.

I knew in that moment that this was never a guy I could be with. So I broke it off before leaving that weekend, saying that I believed we were better as friends. I really had no hard feelings towards him, I just knew he wasn't for me. When he started dating someone else a month later I wasn't bothered at all. Our 5 month relationship had run its course and I was ready for a new chapter.

At the same time, my sister had broken up with her boyfriend of three years and had moved in with me since they had an apartment together. She lived with me rent free with her dog, sleeping on an air mattress in my room. We basically lived on top of each other, but I would do anything for my sister.

Our parents helped her get an apartment of her own about a month later. I helped her move in as she finished up her last semester of her masters degree. After the semester ended she decided to move back home for the summer to save money before her first teaching job started. Her apartment lease didn't end for another three months.

When the lease term was about to end, my sister was nervous she wouldn't get back the security deposit she had put down. She had left a lot of her stuff there that she didn't need back home like kitchen supplies, furniture, a tv, and a gigantic bean bag. She sent me $100 to get packing supplies and cleaning supplies. I spent a few days cleaning and packing up her stuff. My sister came up the following week.

This was the last visit we would have together.

During her time there we finished cleaning the apartment, shampooing carpets, and even wiping down the blinds. I would have done anything for my sister. It was only then, after welcoming her to stay in my apartment, helping her move multiple times, spending hours cleaning an apartment to make sure she got her deposit back, she finally told me she had begun a relationship with my ex-boyfriend.

When she told me I didn't know what to say. I tried to remain calm. This would be eight months after we broke up. I tried some nervous humor saying something like, "It's fine, but I would never be going on a double date with them." I think I even texted my ex saying it was fine.

I tried to play it cool, but I was never fine with it. My sister left for an appointment to get her eyebrows waxed soon after she told me. As soon as she left my apartment, I called my oldest sister. I was crying on the phone telling her what was going on. I didn't know what to do, how to react.

Later that evening when my sister returned from her appointment she took a shower. Like the immature 20-year-old I was, as she was taking a shower I got into her phone and read through their text messages. I found out from the texts that my sister had lied about when their relationship started. They had been together for much longer then she had told me, basically starting their relationship that first month after she returned home.

It was then that my initial shock turned to anger. Not only does she date my ex-boyfriend, she lied about when it started? After I had given up so much of my time in an effort to help her, she waited until she was done using me to help her move one last time before she let me in on her secret.

I don't know why she waited to tell me when she did. I don't know if she was using me to help her move. I don't know why she lied when she told me. I couldn't believe my older sister, who I had looked up to most of my life had done this. It was in that moment, I was done with her.

Three and a half years later, she is getting married to my ex-boyfriend next month. She reached out a single time to try and talk to me, a week after she told me. I wasn't ready to speak to her then, and now it has just been so long. I told myself I was just waiting for an apology. For her to say she was sorry for lying and an explanation of why she did what she did. I have been waiting for her to give me a way to understand her actions.

During this time I have gone through every range of emotion, but mostly I have had to learn to manage my anger. After every accomplishment in my life I would always be angry that my sister wasn't there. She didn't see me graduate college with honors. She missed my fashion show in New York City. She will continue to miss every milestone I will ever have in my life that a big sister should be there for.

However, a lot of what I have learned going through this is that I lost a sister in part due to my own actions as well. For a long time, I felt that as my older sister and the one who had caused the issue, it was her responsibility to fix it. However, we are both young adults and it was both of our responsibilities.

So that's the story, my side of it at least. This story has sadly shaped a lot of my adult life, and it hasn't felt permanent until recently. I have wanted to close the chapter on that part of my life for years, but it hasn't felt appropriate until now. Writing down this story was the first time I felt like it was in the past. Putting this story out in to the world was the first time I have felt free from it.