So sorry this is long. I'm feeling very shaken and emotional right now and just want to better understand this situation. I suspect my ex boyfriend may have had BPD and it would mean a lot if anyone here could shed some light on how this may have manifested in our relationship. I apologize that it's long. 


For the past 3 years, I [F20] have been dating a guy [M29] I met online. We started as casual partners but quickly connected on a deeper level and attempted a relationship which included periods of long distance while I was away from my university for the summer. To be clear, I fell in love with him early on. He however was very indecisive about the relationship and if I could do it over again, I would have read these moments as disinterest--he was hesitant to see each other exclusively, had mixed feelings about labeling the relationship seriously early on, and then ran from the relationship twice more once it became clear I was serious and wanted him to be the best version of himself. He wasn't in a committed relationship for close to 8 years when we met and suffered from what he called severe depression that had gone untreated. I attributed much of his low mood and temper to this. 


Over the course of our relationship, I helped him move into a place of his own, find a new job that was more rewarding for him, reconnect with hobbies, and work on his toxic relationship with his mom (who coddles him way too much for a nearly 30 year old man). However, as we got more and more serious he was increasingly volatile and unfaithful. He insisted on using reddit to solicit nsfw pictures from women (including creating a fake account behind my back to do so), constantly reached out to female friends to the extent that it felt disrespectful to me, spent money on subscriptions to onlyfans accounts so he could chat with the women, and lied about former relationships. He insisted that he pushed the boundaries in the relationship as a form of self-sabotage because he's terrified of being abandoned and putting his best foot forward in a relationship only to fail anyway. We broke up not long, after which I found out about his secret online behavior and confronted him--he flew off the handle and blamed me only to flip to crying and self-pity within seconds. He told me he was so upset he had to leave work and that he hoped he would die that night. I called his family so they could monitor him and he started meds and therapy. 


After progress in therapy and growth in his work life, we reconnected during quarantine to support one another and despite having an incredible time together, he began repeating old behavior with other women and neglecting his therapy/meds. I broke it off because I couldn't trust him, he cried but was understanding, and then I went home. 2 weeks later, he texts me to berate me and blame me for making up the cheating completely, accuses me of abandoning him, and then threatens suicide. That night, after also being horribly verbally abusive to his mother and sisters, he was committed. 


I'm reaching out here because my own therapist suggested he may have borderline personality disorder. I always assumed he lacked a certain maturity, but now that I think back, maybe there were signs I missed and ways I could have helped. He would have an argument with his mom and scream and throw things then sob and need comfort. He would get frustrated when playing sports or video games and throw his equipment, swear at himself, and then shut down completely. But even when I would communicate to him that his insensitive behavior hurt me, he would become angry and accuse me of not understanding him. When I had my wisdom teeth removed, after a horrible day of pain and sedation, I realize he had forgotten about the surgery completely and confronted him, to which he cursed me and said that I didn't seem to care he'd "had a hard week." 


I myself suffer from OCD and my mother has a history of mental illness as well, so I understand how these issues can take over a relationship. I know how things that can hurt others aren't always within our control, especially when the illness goes untreated. I'm trying to understand how to understand the way he treated me. He clearly needs help that I can't force him to pursue and it's best that I keep my distance, but now that I know about how his behavior may be partially related to BPD, it would really help me to understand how this disorder could have been a factor. It makes me sad to think that maybe I could have supported him better, angry to think that simple therapy may have prevented the emotional abuse I suffered, and scared to think that this is going untreated (if it really is BPD). Any help would be greatly appreciated.