Why can't I just let go?

Me and my boyfriend of three years finally came to blows a month ago after he repeatedly went out binge drinking and completely disrespected me and our life together. We live together and over the last year I had a sudden health diagnosis that has impacted my life in many ways. To my boyfriend it seemed that it was more of an inconvenience to his social life than something he should maybe support me with so I wasn't going through the emotional aftermath on my own.

I've been staying with my mum for the last month and in that time, I've written my feelings down in a letter and given it to him to read, hoping that having it literally spelt out to him might make him understand that his selfishness has resulted in me needing to re evaluate our relationship. I said in the letter that I will come back to our flat but I want to continue having my space to gain some independence again and that once I can get a chance to move, I will do it with or without him.

I'm stuck in a situation where I don't want to live in the flat anymore, I can't even afford to live there but I also can't afford to leave on my own.

I'm torn as to whether we should remain a couple while feeling are this tense or make this a clean break. It's difficult because I don't know if I still love him and if not why can't I just let go of him?