Hi Dur1156, welcome to the group. Glad you reached out for support... there's a lot going on in your life.
First of all, am I tracking with you correctly, that you had twins born in 2013? So the kids are 9 years old now? (I typically post over on the "conflicted/family law" board, because my DH has two kids, now teens, and their mom has many BPD type traits. So I try to join in on posts on this board, when I see that there are kids involved.)
So much of what you've described rings true to members here -- unfaithfulness, lack of boundaries especially around sexual situations where "rules" are needed, "flying monkey" friends who support dysfunction, talking a lot about doing something but not following through, actions that really don't seem to match up with spoken words, being an adult parent who is more interested in adult relationships than parenting.
So forward to last month, I have still been seeing my therapist. He said he can't diagnose her, however, she is showing the signs of Borderline Personality Disorder. He recommended I read a book called "I Hate you - don't leave me." So I got the book and have read over half of it. Along with articles online. All I can say is, holy crap! The book describes her actions almost perfectly.
Really glad you are still seeing your therapist. When there's a pwPD (person with some kind of personality disorder, whether diagnosed or not) in our lives, there's no such thing as "too much support". These are emotionally intense and draining relationships. Our self-care, regulation, and stability skills have to be 110%. And your T sounds wise and made the appropriate call -- he can't diagnose someone he isn't treating, yet it is OK for him to recognize patterns of behavior and educate you about a plausible reason it's going on. That matches up with our approach here -- it's less important whether or not the pwPD in our lives has an "official" diagnosis or label or not. What is important is that whatever they're doing is an identifiable constellation of traits and behaviors that impacts us negatively. So our priority is building skills and tools to most effectively cope with those traits/behaviors, whatever they're called. It just happens to be the case that "BPD" is an effective descriptor of a certain grouping of behaviors/traits, which points back to what you're seeing: not taking responsibility, words and actions not matching, blame, low executive function, unstable and chaotic relationships, impulsive and/or self hurtful behaviors.
I just really don't know what to do. On one hand I feel terrible that she likely has BPD and won't get help.
Yes. You've gotten to the core of the issue -- for a pwBPD to make meaningful changes, she has to decide to do something really difficult, which is to see that she is doing hurtful stuff. Because BPD is a shame-based disorder, it means that the one thing that would be most helpful (therapy) is the one thing that is the most difficult for them to do (have someone shine a light on their behaviors). While it's not impossible for a pwBPD to seek and adhere to treatment, it is not a given, and you're right, she has to want to do it for herself. Nobody can externally make her do it. She may have to hit "rock bottom" herself to have that moment of insight, and the hardest part of watching is that rock bottom can be really, really far down for some people.
On the other hand, I am concerned about her mood swings and how it effects me and the children.
You're on the right track to be concerned about how her choices and emotions impact you and the kids. How have they been doing with Mom? Do they have a counselor too? Having a BPD parent (whether diagnosed or not) does have a big effect on kids' development, so it is critically important, as you sort through a healthy way forward, to prioritize their well-being. Your spouse is an adult and can make her own decisions about her mental health... or, sadly, not. Your kids, though, are children, and need you to be the stable parent who supports them.
I obviously can't force her to get help but I also don't know how much longer I can live like this. My therapist called it "being in purgatory."
Again, yes, I'm glad you're understanding that you can't make her change if she doesn't choose to. Though I also understand how heartbreaking it is to realize that. I know this cannot be what you wanted for your marriage or your family or for her. I really feel for you and I'm sorry this is happening.
I do have enough resources financially that I could take care of my kids without her being around. So I feel like maybe I should slowly push her out.
Interestingly, on these boards, there is often (but not always) a sex difference in how BPD parents approach parenting. Dads typically "talk a big game" about wanting to be involved, but drift away to be interested in other relationships, and don't actually follow up on their parenting time. Moms typically get really enmeshed and controlling with the kids, seeing them as supportive extensions of themselves, and try to elbow out and erase the other parent. Your situation is a bit atypical in that your kids' mom seems more interested in drifting away to pursue other adult relationships. Just like you realized about how you can't make her get treatment if she doesn't want to, an analogue is that unfortunately you can't make her "be an involved mom" if she doesn't choose to. The choices in front of you (nutshell version) may indeed involve "letting" her choose the level of parenting that works for her, and that may look like Mom moving out, pursuing other relationships, and seeing the kids for one day a month. That being said, if she is unstable, then it may not be the worst thing in the world for the kids to have one good day a month with Mom where she can mostly hold it together and have a good time with them, versus being with Mom 80% of the time and being exposed to her instability, self focus, and unpredictability for long stretches of time.
I'm glad you're assessing your ability to support yourself and the kids if she were to move out. I hope that provides you with one less thing to worry about for moving forward.
Her statements and actions seem so contradictory. She wants to leave but doesn't do much to further that end. She wants independence but her idea.to achieve that was to live with her parents. She wants to not be treated like a child, but then acts like a child.
All I can say to that is Yes, that sounds really typical.
So, all that being said, have you consulted with any lawyers yet? I think I'm tracking with you that you are at a point of being done with the marriage -- is that true? If so, it's very typical to consult with a couple or a few lawyers to understand your options and likely outcomes in your area. Initial consultations can range from 30-60 minutes, more or less, and can be free or low cost, and typically do not require a retainer. Apologies if you know all this already!
The reason I recommend that is because you will want to protect your kids as much as possible whatever the future relationship between you and your kids' mom looks like -- whether separated, divorced, or other. What I will say is that sometimes there is a "pivot" with moms where for a long time they talk about "just leaving" or "letting you have the kids" or whatever, but if you don't move forward on that, and try to "make them feel better" or "be fair" by "letting them have the kids", they can do an absolute 180 and "pivot" to being enmeshed with the kids and weaponizing them against you. Sadly this is not uncommon. So I'd recommend seeing what lawyers in your area think about your situation, and taking it slowly and methodically for now. Consider documenting your level of involvement with the kids (bedtime, school events, bathtime, making lunch, doctor appts, etc) -- better to have that info and never need it, than need it and not have it.
Anyway, this got long, so I'll wrap it up by saying you're definitely not alone in your situation, and you're wise to realize that you can't make your kids' mom change, so protecting and supporting your kids will be a huge priority for you moving forward. Grieving what could have been, both for your family and your relationship, and moving towards accepting "what is" may also be a big part of your future, and I'm glad you have the support of a therapist as you navigate all this.
Let us know how you and the kids are doing, whenever you have time.