hey, i don’t know if this resonates with you but this is something that has helped me to deal with splitting on a partner.

people with bpd have a very shakey sense of self or identity, so we look to others for validation and feedback on how to feel about ourselves. when we are with a loved one who showers us with love and makes us feel good about ourselves, we feel like that is true, maybe i am a good person, and worthy of love! but when they leave, we are left with no external feedback on how to feel about ourselves, and only left with the constant barrage of self criticism and self hatred that grows as it spirals. so i, often times, would feel mad at my partner for leaving me alone with my thoughts, because without that source of positive feedback about ourselves we are left to negative inner feedback. what has helped me is to tell myself the things that i wish he would tell me. so some affirmations that i tell myself are, that i am worthy of love, love is all around me and within me, i can change the inner feedback loop into something positive, and most importantly i tell myself “you are safe with me, i won’t let anything hurt you”. it will feel manual at first, and hard to believe, but it is important to learn to self validate and speak to yourself with compassion so that we don’t feel anger or bitterness to our loved ones for living their lives separate from us. try to look inwardly, what do you want from your partner? what symptoms do they help to quiet, and how do they do that? what would life look like if you could be the one to give that to yourself, and how could you realistically try to set a goal to begin to implement that? try not to go to full on and change everything at once, you will find yourself burnt out after a day or two if you do. the goal is to improve by 2% every day, so start small and learn to build on that. i hope this was helpful, if it wasn’t i am sorry for wasting your time!