That sounds great- I'm glad it's working!

Yeah, I wouldn't tell her your ex's intentions if you're not leaning in that direction.  It's unfair to her and there's nothing to gain.

I think our brains are trained to think "What would my BPD person want?" instead of "What do I want?"  The latter is much healthier since it's what actually matters.

I think both extremes are solving the problem for them. Either feeling completely rejected, discarded, and abandoned or feeling entirely loved, supported, and important.

Yes Pook she is fully aware of the situation. I met her about 3 months after the breakup as she works behind the bar I go in, instantly had chemistry and would find myself there with just the two of us at the end of the evening talking endlessly about everything. Spent another 14 months before we started our relationship together.

I also am getting the sense that something is going on here.  Like it's pretty normal for pwBPD to cause chaos til their get their way, but usually "their way" isn't something that's an obvious dealbreaker for any relationship, like "I get to cheat, and you need to be okay with it."

But maybe this is typical BPD-behavior and it's just unfortunate that this time she fixated on a "greenlight to have an affair" as the "shiny object she needs in the moment," instead of other stuff they usually want, but then move on from in 5 seconds, like a more attention, a new hobby, clothes, a vacation, etc.  She has to realize though that pushing for the right to have an affair is really a dealbreaker. 

Is she okay with the kids knowing?  I might say that as well, and you're being honest here when you spell that all out, something like: "Look, it's not just me being "selfish" here and keeping you from what you want out of spite.  What are the kids going to think about you cavorting around with a lover?  I'm not going to lie to them and cover for you, and you're putting your wants ahead of any concerns for not just me but our family."

stay strong, man.

The short answer- you don't.  Not in the moment at least.

Think of it this way.  You get bit by a spider.  You fear spiders and hate spiders, so this is a big deal to you.  You're not happy, in fact, you're the opposite of happy and you're in a full-blown panic.  What if the spider was poisonous?  Do you need immediate medical care?

And in that moment, I ask if you want to have tacos for dinner.

Tacos for dinner?  Can't you see what's happening here?  I could be dying and you want to talk about tacos!  How could you possibly think it's time to talk about tacos?!?

For me, it's a simple, normal question- after all, we have to eat, right?  For you, it's a declaration of war because it shows exactly what I care about.

This is how a BPD person is thinking in the middle of conflict...they're appalled that you can't see how badly they're struggling inside and they're shocked at your nonchalant attitude in what's clearly a crisis.  Of course, this is likely all hidden from you so how could you possibly know?  But it's the same reaction.

That's why in the moment, you can't talk about your viewpoints on their ridiculousness.  You simply need to help them get  through it in the moment so they can calm down and start thinking rationally once again.  Once that happens, then you can talk about whatever is on your mind...but never before!

If I think of you as my best friend, but suddenly you tell someone else that you don't even know me...what would I say?

I could tell the truth and say, "But he's my best friend in the entire world!"  And then everyone laughs at me as I feel stupid and rejected.

Or I can say, "I can't stand that jerk!  Like I'd ever say he's my best friend...that's ridiculous!"  Then everyone laughs and I'm on my way to making a new best friend.

If BPDs fear being abandoned, it's much easier for them to abandon that person than actually deal with all the intense emotion of being discarded.  Someone who breaks up with people often likely has huge abandonment issues and their meanness is compensating to hide their pain.

We've all been there and we all knew better.  I can remember so many arguments where I'd just try to listen patiently, to wait it out so it didn't escalate, and then they said one thing that was so offensive, so ridiculous that my mouth started talking before my brain had even processed it.

That means we're human though, and there's no way to be perfect 100% of the time.  If someone is yelling at us, it's only natural to want to defend ourselves.

One thing I've learned is that the time for our personal viewpoints has to wait until the BPD is stable and thinking objectively once again.  They're so hyped up in the moment that defending ourselves comes off (to them) as saying they don't matter, which only makes everything worse.  It's literally a no-win situation unless we focus specifically on their feelings in that moment and deal with that first.

Your current girlfriend knows that you're still married, right?  Even if the marriage is just a technicality, hopefully the girlfriend knows and understands the situation.

If I were in your shoes, and my ex suddenly wanted to get back together, I would not tell my current partner unless I was actually considering it.  I'm re-married so it's not the same thing, but you might feel like that's still an option for you.  And if so, that's fine.  There's no reason to unnecessarily hurt your current partner unless you were actually thinking about giving the marriage another shot.

This is 'projection'; where the BPD accuses their partner of being the guilty one and tries to shift blame onto them. This is a pretty standard BPD symptom.

Not all BPD's show every symptom, there's usually a combination of varying levels. My ex had all of the traits except self-harm and she could lie very blatently to my face then switch off when I confronted her with the facts.

The only thing that is certain is that without her accepting she has problems and being willing to seek help and stick to it, this is what you're going to get all the time, as things will just repeat. The only question is if you're prepared to accept this kind of very difficult relationship.

Hi In4thewin
In my experience validation etc is very helpful when someone with BPD is ranting/distressed/angry or emotional in any way that doesn't refer to YOU. For example if DD is extremely emotional about a friend not being supportive, then validating can really help.

However if the rant is directed at you, then - in my experience - anything you say will be twisted back in attack at you and the episode is prolonged.

This is just how it seems to me from my experience.