A. T. Robertson, the great Greek grammarian as well as a textual critic and general student of the New Testament, tells the following story about
Genesis 2:24: “Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh.” Your Spouse
The shorter reading is generally preferred if the change is intended. This is a reflection of scribal tendency, as a scribe is far more likely in his efforts at clarification, willfully to make an addition to a text. Very rarely will a scribe intentionally add to his text by mistake.