I am miserable, have no fun in my life really the only joy is from my children.
This^^^^.
I've found myself thinking very often that there is no joy in my life anymore. Who would knowingly opt for a life without joy? I think most normal, rational people would run like the wind if they knew beforehand what they were getting into with a BPD partner. All we can do is attempt to minimize the chaos and stress that our loved ones put us through. It takes it's toll though, and you may find that your feelings for this person will slowly change over time.