I never had a sister. That deep relationship that involves confiding one's most intimate secrets to an individual who is morally obligated to keep them for one's own good. A relationship based on trust, but necessarily competitive. As a child, I longed for that intimacy. Luckily, high school came along.

In the midst of all that awkwardness, I was able to develop some of my closest and longest relationships. The best example of this was meeting my best friend. She had no sisters either, so our bond was immediate. We seemed to thrive on the fact that we were similar: we're both spontaneous, organized, "lean in" types who work best in situations we can control, and for 20 years we were present at special moments in each other's lives. But, as is often the case, life was not in perfect synchronicity. And, as with sisterhood, feelings of hurt, resentment, and, no doubt, jealousy arose. Unlike the sisterhood, our relationship remained a choice.

Four years ago, I became pregnant. We had been married for a few years, settled into our first home in San Francisco, and had just returned from a wonderful trip abroad. My husband and I were ready. And three weeks later, we were pregnant. It was exactly as it should have been. It happened so fast, but I had no idea how special a hand I had been dealt. In the United States alone, about 12 percent (open in new tab) of women ages 15 to 44 suffer from infertility. While celebrities like Chrissy Teigen (open in new tab), Gabrielle Union (open in new tab), and Meghan Markle (open in new tab) have brought the topic out of the shadows, the cultural buzz has not even begun to scratch the surface of the many interpersonal relationships affected by infertility I have learned this firsthand. I have learned this firsthand.

For as long as I can remember, my best friend has talked about becoming a mother, stopping in her tracks whenever she saw a chubby baby. Knowing her desire to have a family of her own and the fact that she had struggled for over a year to achieve this, I resisted telling her the news of my pregnancy. So when she asked me to accompany her for a walk a few days before she celebrated her 30th birthday, I decided not to tell her about the pregnancy yet. What I hadn't considered was how in tune we were with each other. As she was tallying up the BevMo orders for that weekend, she sensed my reluctance to have a drink. She exclaimed. I smiled sheepishly, but her reaction was one of pure excitement. I couldn't have been happier. To be honest, I felt guilty for doubting her. She is my best friend.

Her enthusiasm did not last. While I was adjusting to my new normal, her life did not change. As the reality of the situation became clearer, the tension between us grew. It was only natural that my becoming a mother would be a topic of conversation among my friends, but I couldn't help but feel her discomfort whenever the subject came up. I quickly became conflicted, feeling both joy at being able to experience the moment I had always envisioned, but also guilty that it was so easy. I checked in on her regularly, convinced that a happy ending was just around the corner. At the time, I didn't realize that it was not comforting for someone in her position to hear those words. Despite my well-meaning optimism, there was no way to know what the future would hold.

For the rest of my adult life, we saw each other every week. My presence had become an unwelcome reminder of my absence in her life. Eventually we took a long walk to reconnect. On the way home, I felt a certain resolve. But as I began to process what had just happened, I felt restless. We talked about her inability to be around me, to discuss baby matters, to be around me as we both had hoped. I immediately empathized with her and leaned into her feelings. To show solidarity, I offered to check in with her before we talked about the pregnancy. At the moment it felt like the right thing to do, but later it felt unfair. The life growing inside me was worth acknowledging. I realized that I could not let my happiness be buried to her disappointment. It was then that my feelings began to change. What had been an equally compassionate friendship began to feel one-sided.

As the months passed, we both stalled. She assumed I was satisfied with our new arrangement, and I was quietly growing resentful. Then, in March, a few months before my May due date, she broke the good news. She was finally pregnant. I hoped our friendship would be restored and looked forward to enjoying the last few months of her pregnancy without restrictions. I happily answered any questions about the impending birth of our first son without waiting for her response. But something was still not right. I couldn't help but be annoyed. The damage was done. She had simultaneously ignored the most important time in my life. It seemed that only now was I allowed to feel the joy I had craved to feel months ago.

Sadly, I never got to meet the girl. When I saw her email, my heart sank. A few days later, as I left the OB/GYN, our eyes met in the waiting room: me with my 3-month pregnant belly and her with nothing. We hugged and held each other and cried. For a brief moment, under the worst of circumstances, we reconnected.

Shortly thereafter, I took a shower. I called her to tell her that she did not have to attend if she did not feel up to it. She was impressed and said she would definitely attend, but as the day approached, she changed her mind. That afternoon, I glanced at the door, hoping she would change her mind again. She did not.

Struggle is one of our most shared experiences as human beings. Because we are in an increasingly filtered world, it is easy to forget that hardship is the common thread that connects us. In another conversation the week of the shower, a good friend called to share some tragic news. My first boyfriend had taken his life. He was my first and only love. On the day of the party, I should have been there to celebrate, but my heart ached. I knew I had been right to tell her not to come, but God, I needed her. For the first time in months, we stood on common ground.

Almost a year later, we discussed our rift once more. She reiterated that she had done the best she could under the circumstances. Support was a two-way street. Neither of us was wrong. We were simply on opposite sides and could never fully understand the other. That was the hardest part to swallow. As a matter of fact, she did not minimize my feelings; I did. As an otherwise candid individual, I did not speak my truth. And the less I spoke, the more outraged I became. I may have been able to change my perception, but I may not have been able to change her behavior.

For years, I could not understand why she seemed to distance herself from me during her pregnancy. I see now that she simply did not have the emotional range to deal with her and my situation. At the time I thought it was selfish; now I think it was self-preservation. It is a hard truth in life that sometimes we are not enough on our own. And you can only hope that those who know you best will give you some grace. I wish they had.

After almost two years of strain, our relationship thankfully found its way back to the way it used to be. One of my favorite pictures from my hospital stay after the birth is of my best friend holding her son and looking down at him with pure love. As one of only two visitors outside of the immediate family, she was the last one to show up, as I knew deep down I would. A few years later, a picture of her holding my toddler and me, her newborn, in her home. Life, and our friendship, did not turn out the way we thought it would in adolescence. We have our sons, we have each other, and we have a bond that can withstand anything.

Editor's note: The images are by design and do not represent the subject matter of this article.