She is agreeable to a structured separation; that is what she has wanted and even begged me to do for weeks. She is still wanting that, but I need to insert some terms of my own which are close to what you suggested.
Thank you. The link to therapeutic separation is a big eye opener. Looks much like what she wants me to do. She keeps saying this is to fix her and get mentally well enough to fix us.
As I'm sure has been said here many times before, you can't change another person, only they can change themselves. Of course, you can support her as she hopefully progresses in recovery.
I've echoed what someone first stated here long ago, after noting that BPD is a relationship more evident as a relationship is closer,
we are/were too close in our relationships to be heard very well, the immense perceived emotional baggage of the close relationship gets in the way. So, yes, she is likely to respond better to a counselor or therapist who has no emotional attachments with her. Emotionally neutral relationship, that is, warm, helpful but strictly professional sessions.
Often here a separation draws a line in a relationship that is difficult to undo. It's different for therapeutic separations, there are goals and thresholds that ought to be monitored. I can think of two questions... .(1) Can you be informed of her real progress in therapy? (2) After a year or whatever time period, it's possible one or both of you will see the other so differently that you may not get back together, can you both accept that? I guess what I'm saying is that you're feeling this is more of the same old patterns of push/pull, come/go. So much depends upon her making real progress in therapy, also where you two are at that later time.
Does she leave the children with you when she leaves or moves? Frankly, over on the Family Law board the biggest problem is that the disordered parent feels entitled to the children and it's a horrendous struggle for years where our members are fighting to just be parents. If she's leaving them behind then that's not your worry, probably you're worried about her popping in and out of the children's lives. That's not good either but I feel that's a less common (lesser?) issue than the disordered parent obstructing the other without basis from parenting.
I recall there was another member on Staying a few years ago. They adopted special needs children but the mother was in and out of the hospital all the time, even attempted suicide a few times. It was quite a struggle for our member as dad. I think at one point she was living separately. I don't know what happened since then but it was really hard on them.