One of the first things that Kathryn partially admitted to was that there was a relationship between herself and her secretary, Francis Dereham. However, she didn’t admit to everything that Dereham previous had told the guards. Had she admitted to everything, she may have been able to save her head, since a pre-contract would have meant that she was never legally married to Henry VIII.
Kathryn told Cranmer that there was talk of marriage between herself and Francis Dereham. They would call each other husband and wife and they often kissed. However, part of Kathryn’s written confession also mentions that Dereham would kiss others in the house; although there is no mention of him calling other girls “wife”.
At no point did she confess that she had sexual intercourse with her “husband”. She explain that they would lay in bed together but he would never be naked. Whether this is true is often debated. She was a young girl and may have be intrigued. It didn’t help with her upbringing. While her step-grandmother tried to give her an education, there was only so much she could do when a lot of girls would sleep in the same room. They were all likely to get up to something and were at that experimental age. Just because times have change in the things that have become socially acceptable doesn’t mean that hormones and feelings have made any drastic changes.