I understand that the choice of whether to have a second (or first or third or fourth...) baby is the luxury of the young and fertile. The privilege of those with access to effective birth control and partners who respect their desires. Since I (gratefully) fall into these categories, I write from this perspective.
Before I had my first baby (C) I couldn't understand why anyone would opt out of parenthood. Then, the moment he was placed in my arms, I understood. I was forever changed; the load was heavy, almost too much to bear. The transition to motherhood didn't happen for me the way I thought it would. The first year was the hardest of my whole life. Before we had children I thought we might have 3. I imagined a sunlit, chaotic, beautiful home, with children laughing and yelling and and me sitting contentedly, admiring all I had created. After we had one, I wasn't sure I could do it again.
My husband and I plodded along through C's first and second years wondering if and when we should add to our family. I disliked pregnancy and the anxiety and loss of autonomy that came with it, and felt similarly about breastfeeding. As we watched C grow and be the absolute light of our lives and many around us, it became harder to shake the feeling that we wanted to grow our family. At the same time, as he grew, everything became easier, and I would fantasize about a life of travel, simplicity, and flexibility.
We eventually did decide we wanted another. I considered it an investment. Unlike the choice to try for C, which was almost completely emotional, the decision to try for number two was almost completely intellectual. I saw our family with two older kids, and even two adult children. I was willing to tolerate another pregnancy and a certain amount of breastfeeding to get there. Now that I had a toddler, I understood that those early days pass quickly, and that two years of pregnancy and caring for a newborn would be worth it in the long run.
As with most things in life, it wasn't that simple. I had a pregnancy that I lost before my second son (A) was born. I'm not quite ready to write about it here, but it was an early loss, and I am ok. The experience made me jumpy, and I felt like the universe was sending me a message that I shouldn't or couldn't have more babies. So we stopped trying for awhile, and started the loop of questioning ourselves again. One would be easier, cheaper, calmer... but...
Six months later we were ready again. This time, all went according to plan. Our two boys ended up 3.5 years apart, which is spacing that has worked very well for us. (Though as my mom has correctly pointed out, everyone thinks the spacing of their own children is "perfect.") There are days when I still wonder what it would have been like to have an only child, but mostly I sit contentedly and admire the beautiful chaos I have created.