cw: self harm

i haven't been diagnosed with bpd but will be trying to as soon as i can. my boyfriend who has been my best friend for the last 5 years has bpd, it runs in his family and he has some neglect trauma. i struggle immensely with my fear of abandonment, any minor tone or off feeling has me spiralling into an endless pit of worry. i start panicking thinking he must not love me anymore or doesn't like me or has discovered i'm a "bad person". we have an incredibly understanding, supportive, and in some parts healthy relationship.

he understands this and communicates that he's just feeling off. he doesn't talk much about how he is feeling because he feels like it makes it worse and that's his choice, i will not push him to because it's not something he's comfortable with and he knows himself. communication is really important in our relationship so don't take this as a lack of communication. we had a really off week the other week where he was really struggling, he had no energy, didn't want to interact and it sent me into a spiral. i was so bad, had the worst feeling i had ever felt and many panic attacks. i'm really clingy and needy and when boundaries are put into place it feels like rejection. he's someone who likes space when he's trying to get better and i struggle sometimes to give him that.

the other week we were going to have a conversation about some certain aspects in my life that i wanted to run past him, and as soon as we were on our way i could feel something was off. i asked him what was wrong and if he was okay and he said his "normal" feeling or like baseline had just changed. i asked if he felt like it was good or bad and he said he didn't know. we sat down and he basically started saying he didn't feel like the person he was becoming was good enough for me or healthy enough. obviously i reassured him but you know how it is. we talked. we both cried a lot. we didn't even have to say the words break up. we just knew that's what it was. i told him i didn't want to go, that i was trying my best. he said i was putting all of it on me and it wasn't my fault. i told him, just come back, if it doesn't work just come back. it was the most, intense, worst feeling i had ever felt. he said that he felt like our emotions just made each other spiral and that he kept hurting me. but he felt bad that he was the one who was abandoning me and he just thought it would be healthier for both of us. i told him it was okay, i understood. but he was enough for me, and that it was okay. we broke up. he walked me home and i just cried endlessly. i was completely lost and broken. the person who said wouldn't leave had left me, and that meant that there must be something wrong with me. the break up was very introspective and healthy, we told each other we loved each other, no mean words were said, we just knew. 

about 4 hours passed, he texts me and he said he couldn't do it without me, that he had never felt that bad, that he was a coward and should've just spoken to me. we fixed it up, we're back together. but he cut his arm and i felt horrible. he said that it wasn't my fault, he had made that choice after he made the situation and it was a result of his own actions. that made me feel better. we talked everything over and i know he loves me. he goes out of his way to make sure i'm safe, has never been angry at me, and is the best person i know. i know he struggles but i'll be there for him. he's said that he's realised how important i am even more so and that he needs me. this was a very genuine interaction and i love him so much. 

but it's kind of left this fear that he'll leave again, and i'm scared of the feelings i felt when he did for a bit. i think it's made us stronger but i'm still scared. i've talked to him about it but i'm just a bit worried and it's something he might not be able to help me with. 

how can i change how i react to his off feelings, is there a way to think? and how do i try calm this fear by myself or with him?