“I love you but I love myself more”

Just wanting to shout into the ether, because I just need to get this out of my head and go about my day like a normal person would :

A trope I have played out from the giving end so many times, but for the first time in my life? This was dealt to me in the series of brutally intense arguments, accusations and eventually a breakup all over a 3 day period. And it is all genuinely my fault. I have been going through a series of rather unfortunate events that according to a friend of mine that shared their input on our breakup, have fundamentally changed me as a person. And that they “miss” who I used to be. I haven’t been me in so long which makes so much sense…I’ve been growing angrier and more frustrated with myself and overall for so long, hyper focusing on my newly ended relationship because I convinced myself that if our relationship was good and well, it meant that out of all the bad I’ve been through? I had that at least. What a giant mistake. In attempts to uphold this unrealistic expectation, I was dismissive about their feelings at times and in turn pushed them away from me when it came to my own mental health, and other things of the like. I was there for them fully and wholly (or so I thought), but not for myself and as my life fell apart, their mental health followed with it as a witness to it. So they chose to step away after a rather thorny response from me after one of our last arguments that ended with “I do not have to explain myself to you or anyone again ever” — that’ll do it.
I miss them terribly, I’ve been crying for days (not an exaggeration) and have realized that I am in much more shit than I thought, and am as sad of a person as my friend told me. I love them, I miss them, we had plans for the end of this month and on, we had the same intention of seeing this all the way through to marriage. We clicked so well, everything felt as it should and we took care of one another so deeply and lovingly. I’m hopeful that through me learning to have respect, confidence and love for myself, that in turn it results in us coming back together. I’ve already made the arrangements needed for my treatment(s), I’m tired of living this way and I’m tired of letting things fall apart over these phantoms. But that’s genuine wishful thinking. Everyone says it’s for the best that we are broken up right now, and I agree. I really want them back, but I know that this is for the best. Otherwise they wouldn’t have done this, and this wasn’t done lightly and they are in as much pain as I am in currently. Both gutted beyond belief since we did not want to break up. Idk. Only way out is through, as always !