By the way, when you came to this board 13 years ago, you didn't have kids, right? So I'm assuming you decided to have a family with her, and you are fulfilled somehow by this relationship? Has she been a good mother? Did things deteriorate with time?
Things have been up and down. As you mentioned, I somehow thought that having kids/family would help stabilize her and give our lives focus. Despite all I read about BPD and all the warnings from others, that's what I thought. Before we had kids, things felt more stable and hopeful in many areas - physical relationship, money, shared responsibilities. Since the kids were born our marriage has turned more into a "managed" relationship. W has acted more and mor incapable, has become more emotional, and now has more baggage to bring with her. In other words, life became more serious, and the smaller things that carried little weight suddenly feel like they carry tremendous weight.
Is the relationship still fulfilling to me? At times. But lately it has felt unfulfilling the majority of the time. Honestly, I'd probably be happier and much less stressed if the r/s were to end in a constructive (non traumatic) way. That's not because of a lack of love or affection - it's simply a fact that being in a r/s with a pwBPD is inherently stressful.
Is she a good mother? At times, very good. She provides something the kids need, and our kids comparatively speaking are great kids. But clearly the kids want more from her. This is another area that has deteriorated with time. For the first few years, W was more on top of the parenting thing. Now most of it falls on my shoulders.