I have been writing in an online diary to try to get feelings out and I do go to therapy. I talk to her about my boyfriend all the time and the struggles I have with him. I know I can't fix anyone but me, I just don't want to lose him and I am hoping he just needs left alone for a bit and will come around especially since at the beginning of this year he left me in a limbo state with our relationship for a few weeks because he was overwhelmed. I hope it is just him doing that again because he told me he can't promise he won't do it again. I feel it inside like in my gut that I don't think he was serious about us breaking up, just wants time alone. I hope that is the case.
Good to hear that you visit a therapist and do journaling. What's your therapist's opinion about your ex?
Sounds like you are young. Sometimes people think they want something, but upon reflection in the future, are glad they dodged a bullet. Someone can be a "10", when it comes to looks and sexual chemistry, but close to zero when it comes, to something like being supportive and nurturing.
When someone shows you who they are, either by telling you or by exhibiting behaviors, believe them. You may think that some things aren't important right now, but, as years pass, the little problems can become major. Playing the role of a caretaker gets old for most, at some point. Life has its ups and downs for everyone. It's tough if you have a partner that isn't able to nurture and support you in a time of need & you have to always be the nurturer.
Certain behaviors can become a pattern, and BPD traits don't get resolved unless someone wants to work hard to tame them. Your ex seems to be self-aware to some degree, but he has to have the desire to learn how to manage his issues. If you plan on having children, you need to consider genetics, when it comes down to mental health issues. It's more probable that the genetics will be handed down to children to some degree.
Is he seeing anyone about his mental health issues? Has he in the past?
Just suggesting some things to think about. Perhaps you can use this time to meet other people and just enjoy doing some mutually enjoyable activities with others. You may find that you end up with a different perspective and maybe you won't still want a committed relationship with your ex.