Hi guys, I apologize in advanced if this is in the wrong sub; I just want to see things in the perspective as a borderline. I’ve spent the past three years reading every book and forum post possible to help my friend best (now ex boyfriend, also long distance) about bpd, and I really care about him and wanted to help him once he got diagnosed. We’ve been dating for about two years now and things were great—I was no longer his FP, he stopped splitting, and all those extremely toxic signs he used to show were clearing away with the help of his meds and dbt. He constantly talked about marriage and how our lives would play out together, and it felt like cloud nine. 

He started school recently (and cut off therapy), and I could instantly tell his roommate was his new FP. I did what I could as a partner and supported him and his new friendship, but also pleaded for more dates and time together as he’s blown me off every day for a week for his roommate. He gaslighted me with “you’re too jealous, you should know I’m not attracted to him and I’d never date my roommate”. By this point he was pushing me away and conversations became dry, but I just assumed this as school being a pain. 

He hit me with the usual love bombs of “I cant wait to marry you one day, you being my wife would complete me” and 5 days later out of the blue he tells me he’s breaking up with me for his roommate he met two weeks ago because he seems more promising than me. He split during our final conversation and said to never contact him again.

With that said, can anyone with bpd maybe give me their perspective on this? Any advice on what I can do in this situation so that I can get an idea of possibly what’s going on in his head? I genuinely feel like he was the one, and I’m crushed that he would throw away the best thing he’s had for someone he met two weeks ago. Sorry again if this is the wrong subreddit, thank you in advanced.