Hello walktheborderline2: I'm sorry you are confronting such a difficult & convoluted situation. I don't know as there is much I can offer with regard to this. But I saw that no one had replied to your post. So I thought I would. Personally I would have to say that this situation is so fraught with potential landmines it is a road down which I would fear to travel. So I would like to validate all of the feelings you are experiencing.

I would have to say that, personally, family relationships have never been important to me. I have left many people behind in my life. So what your fiancé is doing, as far as moving all of these family members & ex family members to where the two of you will live, is beyond my ability to understand. From my perspective, this is a perfect example of divided loyalties. And, while it may be admirable on the surface, it strikes me as creating so many potential problems that the thought of it makes me shudder.

I would be kidding both myself & you if I were to suggest that I have any worthwhile suggestions to offer here. From my perspective, what you are perhaps going to need to do is to get with your therapist if you have one, or find one if you don't, & begin to explore in depth & over time what this all means for you & how you will handle it as the situation evolves. There may also be some value in you & your fiancé participating in some couples counseling. If he will not, this could be a red flag, to my mind.

Your title asked if a person with BPD can be happily married to anaother person with BPD. I don't know the answer to that. I presume it is possible. But, to me, the fact that the two of you each have been diagnosed as having BPD is almost a side issue. What is of real concern here is all of the complicated interpersonal interactions that are going to have to be navigated in order for this whole arrangement to succeed. I wish you all well...