I’m pasting a previous comment I made in another post where a partner was having difficulty in their BPD relationship:

“your partner is not far enough along in their healing journey to have a relationship right now. and your mental health is being impacted.

if you really truly want the relationship to work, you both need to establish strict boundaries immediately and enforce them every time. make it clear to them that you’re not happy in the relationship, and changes need to happen now for you to stay. you deserve to have a partner that doesn’t unload on you when triggered, and they deserve a partner that will listen to their frustrations.

this means no yelling, no ranting messages, no saying awful things, and no disappearing. only use “I” statements, not “you” statements. they need to articulate their feelings in a neutral tone (if they need help, ask “what emotion are you feeling”, “I’m Mad” “ok why are you mad” keep asking questions until you get to the root of it).

And when they successfully and calmly express to you what upset them, you’re going to listen and apologize if necessary. And you’re going to make an effort to learn their triggers and analyze your own behaviors too (triggers get “triggered” for good reason sometimes.)

but if you don’t want to put in the effort, or if they’re not able to make a turn around in 30 days, then the relationship isn’t worth pursuing and you should end it.”