Hi SunSea Tea,

I'm glad you posted—welcome. A relationship with someone with BPD can be very challenging, as you well know, but it can be rewarding as well, because the challenges engender so much learning about ourselves. That self-knowledge can be empowering and help us as much as our partners get through the trials that come with close relationships.
You've found a great place for support. The members here have been (or are) in similar situations, and understand what you are going through. And the site has tons of tools to make things better.
I can imagine your collective sighs of relief at at least having the possibility of something that can explain what you've been going through. Diagnosis or not, the behaviors, and your reactions to them, are issues that can be worked with.
Have you thought about therapy for yourself, individually, SunSea Tea? It can be very helpful, especially after having gone through a bout of infidelity.
How old are your children, and how are they dealing with your the emotional ups and downs?
Keep posting, it really helps. We're here to support you.
heartandwhole