After years of infertility, we adopted a 3-year-old boy named Sam. On the first night at home, my husband Mark offered to bathe Sam, but moments later, he rushed out, panicked, shouting, “We must return him!” His strange reaction became clear when I noticed that Sam had the same birthmark on his foot as Mark.

My heart sank as I realized that Sam might be Mark’s biological son. After a DNA test confirmed it, Mark admitted to a one-night affair while we were undergoing fertility treatments. He had tried to forget about it, but seeing the birthmark brought it all back.