I have bipolar II as well as BPD traits, so my experience may be different from those with "only" BPD, but I think this a problem common to all of us. I have alternated between hypersexuality and near-asexuality in every relationship. My level of attraction depends entirely on my mood and whether or not I'm splitting on them (sometimes for no reason that I can even identify). When my attraction vanishes, I feel incredibly depressed, which results in further loss of attraction, which results in more severe depression... Because this vicious cycle has played out so many times, I now feel panicked at the first sign I'm losing attraction. I'm continually monitoring my level of attraction, which makes me extremely anxious. 

I just started dating someone and I don't want this pattern to take hold again and destroy something with the potential for a long-term relationship, but I'm already noticing dramatic changes in my level of attraction to him. I want to tell him about how my attraction changes but I'm not sure how to broach the topic without offending him somehow. If you've experienced this, have you navigated it?