CONGRATS!!!! Robert Griffin III Gets Engaged On Mothers Day To Grete Sadeiko! [Pics] — RG3 is about to sign a contract … a marriage contract — ’cause he’s engaged to his girlfriend Grete Sadeiko … who just announced she’s’ pregnant with the NFL star’s baby! Robert Griffin III popped the question to the Florida State University track star during a day out to the beach in Fort Lauderdale … popping the question while decked out in a red suit.