In 1541, Dorothy embarked on a love affair with William Parr, Baron Parr of Kendal, who would later hold the title of 1st Marquess of Northampton, after Baron Parr's wife, Anne Bourchier had created a scandal when she ran off with her lover, John Lyngfield, and shortly afterwards bore him an illegitimate child.
Dorothy's affair with Parr lasted until 1543, when he began to court her niece, Elizabeth Brooke, who had also been one of Catherine Howard's Maids of Honour up until the Queen's execution for High treason. It was during that time that King Henry himself was courting Parr's sister, Catherine, whom he married in July. Dorothy entered the new Queen's household as one of her Maids of Honour.