The sex was amazing and intense, but I've had better.
In all seriousness, I think it's a topic worth personal exploration. It's important to identify what needs of ours were being fulfilled by our relationships. Sex can be one factor that keeps an otherwise toxic relationship going.
If i could find someone normal that was on her level sexually i would be all set

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"Normal" is a relative term... .and we all are broken in our ways... .but I've found that there are plenty of sexy, fun, adventurous people out there who are also genuine and capable of mature adult relationships.
I've also found that pwBPD tend to use sex as a weapon and means of control, rather than enjoying it for what it is. This is obvious sometimes in the way they approach sex... .do they ever seem to be able to truly let go and enjoy themselves?... .and also in the way they will withhold sex from a partner, as punishment or other means of exerting power.
Even knowing this, I am still turned on by my exbf, and maybe always will be. The emotional intensity, idealization, intermittent reinforcement, sheer personal chemistry, complementary proclivities, and just plain great sex -- it all combined to make something quite addictive.
But I realize that he is certainly not the only person who can fulfill my needs... .and that I need to take care of myself first in order to find people who can do so in healthy relationships.
Is that why we still dwell on them . looks like they had a very powerful weapon ?
The weapons they have against us are the ones we allow them to use. Are you feeling like this is the strongest "weapon" your ex used? If so, why? What do you think this might be telling you about yourself?