Hello, lotusblossom &

I'm really sorry for all the trauma and hurtfulness you are going through regarding your partner and his relationship with his son... .It's terrible to see things go on that you know need to be remedied, but feel like you have no power to change them. There are a lot of Stepparents on this Board, and I'm sure some of them will show up to tell you about their own situations and how they have dealt with them. I, myself, have an adult son also with BPD (he's 37), but his Dad is my Husband, and we've worked with my son together and don't really seem to disagree with the ways we handle things.
As far as your second question, giving ultimatums rarely work... .And I suppose that the problems would be multiplied if the ultimatum came from someone who isn't his Mom or related to him. Is it in his best interests to see a Doctor and get on some sort of medication? Of course, but unless he can admit that he has a problem, realizes he needs help, and then follows through on getting that help, there's not a whole lot you can do to "make" him do it.
What you
can do is learn all you can about BPD, and figure out a good strategy for how to deal with your partner and his son, that works for
you... .Have you had the chance to read all the
links to the right-hand side of this page? The
TOOLS and
THE LESSONS? There are
Feature Articles linked to under the photos at the top of the threads page on this Board, and they are also very enlightening. Let us know what you think of them, and if you have any questions about them, and I'm sure there will be other Stepparents chiming in soon, lotusblossom