How is that news? Its been happening for the last gazillion years. You don't need a research to tell me that. Its like built into our DNA.
Anyway, the research is about the "why", not a proof that it happens. And their conclusion is that "what determines whether power elicits extradyadic interest is not power perceptions alone but rather the feeling of having a higher mate value than one’s partner". i.e. power => confidence => cheating, not power => cheating directly.