Hello momtomany,
I'd like to join the others in welcoming you to our BPD Family.

You poor thing! I hear your heartbreak, sadness and guilt. I'm so sorry to hear you're repeating a chapter of BPD in your life after you thought you were done with it. That is so heartbreaking! I felt pretty depressed when I learned my DD17 has BPD as well. The realization that my only child has a bona fide mental illness was devastating. I understand the exhaustion and frustration and guilt you must have!
Anyway, our next child is getting married shortly & DS wants us to fly him to the wedding.
I don't want him there. The child getting married isn't much interested either. The other kids think that he will ruin everyone's time. DH is adamant we don't pay for him to come.
Momtomany, did you read what you wrote? You actually seem
very clear about this. Then you go right to guilt... .
Still I'm his mother. I'm in physical pain from the anguish he causes us. Maybe I'm a sucker for punishment? He manipulates that.
I'm lost & devastated. Don't know what to do.
This may sound harsh, but I think you DO know what to do. You're just tearing yourself up with guilt about it, aren't you? You don't have to make yourself miserable to say no to your son! There is an article somewhere on this site about FOG (fear, obligation, guilt). Three things we all know too well when dealing with BPD. When I find it, I will post a link to it for you to read. The other thing I hear you struggling with is your boundaries, which is also a very common problem for us moms as well. I think many of us have a recording in our heads telling us, "A good mother should... ." "A good mother would... ." And yours is, "Still, I'm his mother... ."
In the meantime,
please focus on nurturing yourself so you can feel the excitement and joy about the upcoming wedding. I'll say it again. You don't need to punish yourself for saying no to your BPDS. What purpose does that serve?
I have been saying the good ol' Serenity Prayer a lot lately. Maybe it can help you let yourself off the hook?
God grant me the Serenity to accept the things I cannot change, the Courage to change the things I can, and the Wisdom to know the difference.
You can't change your son's BPD. (Serenity)
You CAN set limits on what you do and don't do for him. (Courage)
What is your wise mind telling you?
There are so many aspects of your post that resonate for me! But what resonates most of all is the self-torture you're putting yourself through about this because I do this too! I know it hurts to say no to your son, and I know you feel guilty. And it will be sad if he isn't in the wedding family photos. But I think you can end your anguish if you just weigh the pros and cons and then stick with your decision. I said before, you already sound pretty clear to me.