With BPD Waifs, ya better shelve your fantasies of actually HELPING them.
The Borderline Waif always seems fragile and pitiful. It's not uncommon to think they'll decompensate the moment you leave 'em, but this is your arrogance. The truth is, Borderlines are masters of self-sabotage, and whether life throws 'em curve balls or they create their own catastrophes, they always land on their feet.
How did that gal or guy survive BEFORE you showed up? If you have unresolved Codependency issues, the guilt you feel about withdrawing your support, attention and care can keep you trapped in a never ending cycle of putting Their feelings, desires and needs before Your Own.
Under these conditions, you can't help but experience some loss of Self. You've consistently back-burnered Your feelings and needs, and the Borderline (having no capacity for empathy) is happy to keep letting you do it.
Most do not understand how incredibly resourceful and resilient the Waif is! She or he has been surviving emotionally since infancy, and they relish the episodic feelings of empowerment they derive from continuing to do so. For many, it's a game to them, to hook a big fish. You might have concerns that your ex has replaced you so fast, but seldom do a Borderline’s bedsheets get cold, in-between a litany of romances.
The BPD Waif may threaten to kill him or herself if you leave, but this is merely Emotional Blackmail that's meant to manipulate you into caving into their control. Borderlines LOVE to threaten and warn, yet practically NEVER follow through.
When you leave a Waif-type Borderline, they may go thru a fairly brief setback stage, but they WILL reconstitute themselves. Your departure works kinda like shock therapy for 'em. At first they feel a bit lost or hopeless~ but within a relatively short time, they're taking a self-assessment inventory, which often motivates 'em to lose weight, change their hair style and/or color, buy a new wardrobe, and morph themselves into someone quite optimistic about reentering the dating pool, so they can snag themselves a new benefactor.
Even therapists may feel sorry for the BPD Waif, who seduces by eliciting pity from others. The thing is, if there are powerful narcissistic traits at a Borderline’s baseline, are often remain 'lifers' under psychotherapeutic care, due to believing they can "fix themselves," and don't really NEED your assistance. It’s all about control for them. If you’re in the driver’s seat, they’ll act-out and undermine themselves, just to get more attention from you.
These people don't WANT to grow, heal or change (it's too unfamiliar and scary for 'em), so clinicians treating these clients often experience significant frustration and therapeutic burn-out, while working with 'em.
They're resistant to following and implementing guidance and practical suggestions/solutions, so there's a lotta circling the drain that happens in the therapy room. You may hear the same exact complaints regurgitated over and over, yet no action is taken by the client that would advance their 'stated' goals or aims.
It's not that you won't come to care deeply for these people, and routinely go the extra mile to help them climb out of the pit they're in... but misery is familiar and therefore comfortable for Borderlines, and it's unlikely you're gonna help 'em surrender it... not in THIS lifetime, anyway.