closed the gap, broke up a year later. 23M, 24NB (need advice, but also just seeking support and community)

i feel like my life is falling apart. i know i need to keep my head up, focus on myself, take time to process, etc etc etc. but i'm at a complete loss. we live alone together. they broke up with me because of some really personal stuff that i don't blame them at all for, i asked them if there's ANYTHING i could have done, and they told me it hurts so much for them because i did everything right.

i'm using a burner (and i'm on mobile, sorry if the formatting is weird?) and i don't want to give away too much information but aside from the very REAL shit my ex is dealing with, i am also questioning if they are having delusions. please bear with me here. i think they may be experiencing erotomania, i'd look it up if you don't know what it is, but real life shit aside they've also dumped me because they think they're destined to be with someone else who lives on the opposite side of the country who they have little to no contact with and the two of them have zero real relationship. i'd hardly call them friends. there is truly nothing i can do about this. i can't tell them they're delusional because they're going to take it as me trying to get them back. to be completely honest, i don't really even know if i can stand to be in a relationship with them after all this.

part of me believes that this will all blow over, their head will clear, and they'll realize what happened and how much they've hurt me. the other part of me doesn't care. how can i trust them with my heart again after all of this? we were going to get married. we've been together for YEARS. i've never been so lost and confused.

i don't expect anyone to know what to do about the magical thinking. i just need someone to hear me and sympathize with me. i'm in my 20s, i know i have so much waiting for me in my life that i have to stick around and see. i just feel like everything is falling apart.