After Elizabeth's stepmother gets remarried in the film, it shows her naked from behind as she and her husband embrace. They're both shown falling into the bed up close. No full nudity.
Elizabeth's stepfather was a creep who behaved abusively towards her the entire time she lived with him and her stepmother, visiting her room early in the mornings and touching her when she told him not to.
Mary Queen of Scots is shown twice making love to a husband, once just her bare back from behind and the second time in bed with her husband sitting on top of her.