Hi hopplesslyinBPD,

I'd like to welcome you to bpdfamily. I'm sorry that you're going throughput this, from what you're sharing with me hear, she's splitting if she has bpdfamily, splitting is a primitive defense mechanism that protects against anxiety and stress, a pwBPD don't see people as an integrated whole.
Good people have bad qualities and bad people have good qualities. She's seeing you as all bad for now, there's also triangulation. When there's a lot of stress between two people in a r/s sometimes a partner will seek out a third person ( it doesn't always relate to another person, sometimes it can be working long hours at work to avoid the other person) to alleviate that pressure.
Your post strikes similarities with my story, I had a lot of conflict with my ex wife because it was an erratic r/s and I didn't understand why she was acting the way that she was, I triggered her fear of abandonment and she immediately started to see another man in our marriage. It wasn't that straight forward, there other elements to the demise of our marriage, for example she wasn't returning to her emotional baseline, if she was, sh wasn't there for very long, so instead of working on the marriage she started an affair.
That being said, I suggest to read as much a you can about BPD, you'll quickly see the benefits and become proficient over time. It helps to talk to people that van relate with you and offer you guidance and support. I'm glad that you decided to join us