I believe Peter Ho was attached to Jang Nara for quite awhile, but both never admitted in public that they were going out. There were also rampant rumours that he has a serious gf called Peggy who isn't in the entertainment line. But when he was promoting Unbeatables last August, he admitted to the media he wasn't seeing anyone. And then also mentioned to his fans (on his weibo) during his birthday party last September that he's so busy with his career, he doesn't have time to think about love now.
Treat for ChineseChik - vid of Peter in Paris during his commercials for Starwood Group.