What is the ruling on a man who marries a woman and subsequently marries her sister while consummating the marriage with the second sister?

Primary text

If a man marries a woman and then marries her sister, and consummates the marriage with the second sister, he must cease relations with the first wife until the waiting period ('iddah) of the second wife concludes. This ruling is established because he would not be permitted to contract marriage with the sister while still married to the first wife unless her waiting period had ended. Similarly, sexual relations with the first wife are impermissible until the waiting period of the sister he has entered into marriage with has also concluded. This view is attributed to Ahmad.