Hi countrygal,
I wanted to join
Learning2Thrive and say welcome

You are not alone many members are in the same position you are, I'm glad you've reached out. It is often hard for people who have not experienced BPD to see it. People with BPD are often able to appear functioning to those not close to them, but it becomes more and more apparent the closer you get to them.
I'm on these boards because my significant other (SO) has an undiagnosed BPD ex-wife (uBPDxw), and when we first started dating he was very honest and up front about his ex, but I didn't
get it right away. But as things progressed I found myself always asking "why" and getting angry... .why was she being so cruel to him (parental alienation), why couldn't he get their daughter with a toothache to the dentist (neglect), why did she pull their daughter out of the classroom to home school her (neglect)... .why, why, why?
When you have the chance can you tell us more of your story? We have lots of tools, we can give support, and we can share ideas but could use more of your story to help give us some direction.
How long have your child and his spouse been together? Do they have children? What does your relationship with your child's spouse look like? What are your biggest issues or concerns?
Again welcome

I'm glad you decided to reach out.
Panda39