US Constitution, Article VI, Clause 2;
"This Constitution, and the laws of the United States which shall be made in pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land; and the judges in every state shall be bound thereby, anything in the Constitution or laws of any State to the contrary notwithstanding." [Emphasis added]
Given the Constitution clearly states in plain & clear English that a treaty made under the authority of the Constitution becomes the "supreme law of the land", there is no way any president can unilaterally terminate a treaty ratified by the Senate. The Framers established the Constitution to rid the people of the States of the Rule of a King who could do what he wished, like a Crazy George III or a Trump!