I've been pretty much where you are. She told me way more than I needed to know about the new relationship and it was very very painful. I was isolated too, and found that reaching out to family and seeing a therapist saved me. It takes time and what you are going through is completely normal. The worst part for me was not getting the closure, and getting my hopes up even in the face of growing evidence that she simply is not well and she needs to get help before she can be in any relationship. For me I need to be whole again and heal as well before I can be in a relationship.
I hope you get better, take it one day at a time and if you can watch tv and do just about anything to keep your mind busy, see friends or family, an minimize interacting with her, then time can help to heal. Also if you imagine what you were like before you met her, and what you want your life to be like in the future, how it's different and how you've grown, that could help too.
Stay strong and know you're not alone.
She left awhile ago. It was a 10 month thing. She found a new guy. I think she has many BPD symptoms but is high functioning maybe not quite BPD. Anyway, I'm very sad. She wanted to be friends and I did that but didn't want to hear about her new relationship. She forced some superficial details on me via text message today. I told her how much I lived her and gave her a chance to come back that she probably wouldn't take. I needed to try to be a courageous me but I had low hopes.
Now, I'm gonna try 2 move forward without much contact, which she is ok with, and continue to see the therapist. And not date right now.
That's my plan. I can still work (sleep may be hard) but I think I'll be ok. Any suggestions are welcome.
She sent me a pic of her with her new boyfriend, it helped me get over "denial" but im not sure how I feel about that. Gives me a path to move forward though.