Rupert possessed a charismatic personality and was widely considered attractive. He had numerous admirers throughout his life.

Rupert had a long-term relationship with Frances Bard, the daughter of a Royalist nobleman. They had an illegitimate son, Dudley Bard, who later became a soldier.

Rupert became involved with Peg Hughes, a well-known actress. They had an illegitimate daughter, Ruperta, who was later recognized and provided for by Rupert.

Rupert showed genuine affection and concern for his daughter, Ruperta. He ensured she received an education and provided for her financial security.

Rupert never married and did not have any legitimate heirs. His illegitimate children were the only direct descendants he recognized and supported.