tldr; when did you tell your SO about your BPD? Why did you do it at that time? And how did they react?

Hi all! In need of some advice right now. I've been in DBT for about three and a half months now. I've been feeling great for about two and a half of those. I feel like things are coming together very well for me (new work, friends, relationship). However, I can also feel the BPD symptoms giving my peace of mind some major pushback.

I recently started seeing a new man (I am a 25-yr-old female). Things have been going great. He noticed my scars, and I told him about the self-harm but didn't touch on anything related to the illness... just that I'm seeing a therapist and working on myself and my happiness. He wasn't bothered by any of this and was totally supportive of me.

Last night, we went out drinking with some friends. I got drunk and started to dissociate heavily. When I dissociate while drinking, I'm just a short distance from self-harm. When we got back to his house, I stole a knife and lashed out at him a bit so he'd leave me alone and I could cut. I went into the bathroom to do it, but fought back with every ounce of my might so I wouldn't. Even though I felt dead inside, with that heavy weight on my heart that I just can't explain, I knew it wasn't worth it. I went into his room and told him what I was going to do and gave him the knife. He was upset about it, and it probably freaked him out. However, he was very compassionate about the whole thing.

I want to tell him about what I'm going through so that he has context for my actions. I've severely dissociated around him twice in the two weeks we've been seeing each other romantically. I want him to be able to understand that this is a battle I am burdened to fight but that I also am very committed to being well and leading a happy life. I want him to know about my crippling fear of abandonment, fear of feeling, the crushing emptiness and the depression, the relief of self harm and the desire to commit suicide. But it's also a new relationship, its fragile. I don't want to scare him, but I also don't want to date him if he's scared because this is who I am, though I work to be the best version of me. Sometimes I slip up like last night. What should I do?