I've never actually been diagnosed as having Bipolar Disorder although one psychiatrist I saw said she thought there might be a "bipolar element" to what was going on with me (whatever that means.) Having read just a little bit on the subject of Bipolar II I can see where that diagnosis might actually have fit though.

I guess the thing I wanted to say was that, when I was young (I'm an old geezer now) my own hypersexuality led me down some dark, disturbing & destructive paths. You asked if hypersexuality is a common problem for people who have bipolar disorder. And I can't answer that. What I can say is that, whatever my diagnosis might have been way back then, hypersexuality was certainly a big problem for me.

Here's a link to an article, from PC's archives, on the subject of hypersexuality, sex addiction & bipolar disorder:

Bipolar Hypersexuality or Sex Addiction? | The Impact of Sex Addiction