In our marriage prep, we'd heard about the stresses of NFP. We'd heard about the difficulties of choosing to abstain during times of fertility rather than choosing a form of birth control. We'd heard that NFP could cause fights and at times resentment. Everything we'd heard about the difficulties of NFP prior to our marriage was in the context of using NFP to avoid having. children (or TTA). Clearly, we weren't using NFP to avoid having children at this point in our marriage. It followed then, that there should be no difficulties caused by using NFP, no stress, no strain on our marriage.