PARADISE VALLEY, Ariz. — Michael Phelps took the plunge in June, secretly marrying his longtime girlfriend two months before the Olympic great completed his last gold-medal haul. The Arizona Republic reports the 31-year-old swimmer wedded Nicole Johnson on June 13. That’s a little more than a month after the former Miss California USA gave birth to their son, Boomer. The newspaper has posted a copy of a marriage license that shows Phelps and Johnson were married in Paradise Valley, Arizona.