Using statistics from the American Psychatric Association, 2% of the population have BPD and roughly 2% have bipolar. The US in December of 2008 has a population of roughly 305 million. That's 12.2 million affected by either disorder out of the entire population. In the grand scheme of things, that's not that many. Now what percentage of the population is considered attractive? Let's say the top 20% are considered attractive. Out of that 20%, let's say 10% are women. So that's 30.5 million considered attractive, and if we say, I don't know, 8 million affected by either disorder are female, and say 6 million of those women are attractive (being generous), then 6 million out of the 35 million (almost a quater) are both attractive AND affected by either BPD or bipolar. That's unlikely.
I don't think this is either a case of causation or correlation between beauty and mental illness. Even if the numbers were in your favour (and they're clearly not) that wouldn't even say that one thing is necessarily correlated with the other.
Also, avillax, if 6 million people in the US (assuming you live there, of course) are affected by BPD, what are the chances that you're three prior relationships all have BPD? 6 million out of 305 million? That's 2% out of the population? That's not bad luck, that's just very unlikely. I don't need to know you or your situation to realize that's crazy!