Here's an article that suggests a love interest. It's from a Taiwan based site

http://www.wantchinatimes.com/news-subclass-cnt.aspx?id=20120408000105&cid=1101

It seems a fairly unsubstantiated claim and if you read the article in the wall street journal (quoted in the article above) you'll see that they claim Gu Kailai asked several members of Bo's inner circle to divorce their wives and swear loyalty to the family. Was she having affairs with all of them?

http://online.wsj.com/article/SB10001424052702304444604577337951998961744.html?mod=googlenews_wsj