I have ASD and don't know how to keep coping with ADHD partner

My partner and I have been together for a few years now, and the beginning of the relationship was amazing. They were attentive, funny, charming, and really seemed to care about me and value me in ways I felt and understood. It all started to fall apart and got even worse when we moved in together. I feel like I got tricked into being stuck taking care of an adult child who wont take any accountability for their actions or inactions. They promise and never follow through, they've accidentally started fires by leaving things on in the kitchen, broken my items by being careless, forgotten our child, left their car on for hours, failed to pay bills, damaged my car in an accident, and so much more. On top of this, they just expect that I can be fine listening to them vent about anything they want. Or talk about anything they want. Yet when I try to talk they just interrupt me and go on about whatever they want to talk about. At this point I'll just stare at them and listen, or just pretend to listen. They don't respect me enough to actually listen or care about my feelings it feels like. Though they expect me to coddle them when they're upset, they expect me to pay for their things in emergencies ($700+ for car tires, $500 for glasses as they insisted on the bells and whistles, $700+ on car insurance because they didn't want to do monthly payments and are "not able" to manage their money), be okay when they lie or break commitments, and so much. They're a funny a person, they're nice, and they're not physically abusive like people I've dated in the past, but the emotional and financial stuff is just getting to me.

At the end of the day they just seem to expect I'll be all better, no matter what they put me through. Be it hiding in the bathroom watching porn and lying about it, but then spending hours on video games and their phone just to fall asleep moments after crawling into bed after saying we'd have time together. Or all the other things I've mentioned, I just don't know what to do anymore. We have a child together, and I don't want to go through a divorce, but I don't even feel like I want to exist anymore because every day requires suffering, false promises, and "changes" that maybe last a day or two at best. I know they're not like this to personally hurt me, but they refuse to understand how hurtful their behavior is. Even though I tell them. Nicely, not nicely, it doesn't matter. I'm not listened to until I get to the point where I have a meltdown because it's all too much and I don't know what to do. I want to run away from my life, and never have to exist as myself in any capacity because I can't do it anymore.I have to stay alive because of the child and our pets, but I really don't want to