It's no secret that experiencing infertility can be hard on your sex life. In fact, I don't think I've ever heard a client tell me that their sex life had improved once they realized infertility was an issue. Typically, the scenario goes as follows: at first, there is great excitement as a couple begins to try to have a baby. However, if things don't work out relatively quickly, anxiety sets in, and sex becomes a more scheduled and anxiety-fraught affair. By the time infertility treatment begins in earnest, sex has become associated with feelings of failure and unhappiness, and couples sometimes struggle with maintaining a healthy sex life.
Many times, I've had clients tell me that they feel that because they are infertile, that sex has lost some of its meaning for them. After all, sex exists for the purposes of reproduction, and if having it can't achieve it's purpose, they experience feelings of loss and failure.
Although this reaction is understandable and predictable, it seems to have more to do with cultural values about sex rather than the realities of the situation. Although I'm no evolutionary biologist, I would argue that reproduction is only one of the purposes of sex, and perhaps not even its most important purpose. This is because for human beings, a sexual encounter rarely produces a child. Even in the case of the Duggars, only 20 or so of their instances of their intimate moments resulted in a pregnancy. In contrast, many other species only engage in sexual behavior when reproductive potential is at its highest--cats, for example, who only participate in sexual behavior when the female cat is ovulating.
For humans, then, sex plays another very important role--sexual behavior leads to affiliation. A couple's sexual intimacy keeps them close to each other. This had several evolutionary advantages. Historically, human beings have survived better when they lived in group. Their offspring tended to survive more often with more adults available to protect and care for them. Thus, sex really isn't merely about reproduction.
In the history of Western culture, sometimes the reproductive aspects of sexual behavior have been emphasized over its affiliative aspects. In recent times, societies' values about sexuality have changed. Interestingly, from a psychological perspective, when it comes to infertility, we often take a more reductionistic view, focusing only on the parts with which we struggle.
Thus, if you are finding that your sex life isn't what it used to be since infertility, keep in mind that for human beings, sexual behavior isn't primarily about reproduction. Rather, for us, sex is primarily about forming and maintaining an important relationship. Even if you are infertile, you can still be successful at feeling close with your partner. In the end, the survival of the species may depend more on that than on reproduction per se.