A top Republican fundraiser will stop making payments to a former mistress who signed a hush-money agreement that was negotiated last year by Michael Cohen, President Donald Trump’s longtime lawyer.

Elliott Broidy, a Los Angeles venture capitalist and former Republican National Committee official, agreed to pay former Playboy centerfold Shera Bechard $1.6 million—in eight installments, beginning late last year—to keep quiet about her affair with the married donor, The Wall Street Journal reported in April.

Now...