[Objective]

Love the emotion and honesty put into words here. I'm in a similar situation right now after having taken the "never be friends with an ex" since the dawn of time. Randomly met my ex after being broken up for a little less than year a few days ago.

Only difference from your perspective to mine in your verse is this part:
If I could send a text, you could help the mess,
^This I think is unhealthy and something to be worked on with close friends or a therapist. That's a lot of heavy vibes for people not having those elements in their lives (if they do, it can be another toll) and/or responsibility to put on another human being, especially if they come from a better household themselves and deal with things differently.

I'm babbling on at this point. Besides of what Lars said and the fact I enjoyed your piece, part because it was relatable and contained emotions I've dealt with recently as well, is this:

It was me who sat us down to start the end of us,
Yet I never understood how important that our friendship was,
^I would consider removing syllables that doesn't add anything to help with flow and being more poignant in its message. Words like "yet" and "that" can both easily be removed for quality of life reading and flow.

Overall I enjoyed the read and what you're saying, and feedback given so far in order to improve further is golden.