Expert equestrian Hillary Dobbs, 21, daughter of former CNN talking head Lou Dobbs, celebrated her recent $50,000 win at the Holiday & Horse Grand Prix by getting engaged to longtime beau Roy Wilten. The lovebirds were taking an evening swim at the Palm Beach International Equestrian Center when Wilten, 24, a Dutch horse dealer, got down on one knee in the pool and popped the question, spies said. An excited Dobbs — who’s also a full-time Harvard senior — woke her dad and mom, Debi, at 1:30 a.m. to tell them the good news.