Dismissive Avoidance, incompatibility or something else?

I don't think there's a TL;DR version of this but I'll keep as brief as possible.

I (45F) have been with my partner/boyfriend (59M) for 1.5 years. We met online and it got serious fast. I was freshly out of a very short (3 month) relationship with an old flame that ended when he broke up with me. Prior to that I had ended a 5 year relationship with a man who was utterly disinterested in me sexually/romantically after the first year or so. Prior to that, I was married to a man who cheated on me repeatedly until we finally split up after 10 years of marriage. These are all relevant I believe.

My current partner is very enotionally intense, and he recently discovered he very likely has undiagnosed ADHD. He's used this to justify some of his behaviours, which I accept to a degree, like struggling with cleaning, time management and anger outbursts. He lives 100 miles away so we are mostly long distance, however when he comes to stay it's for weeks at a time. I work full time, he doesn't work. I have struggled with that element of our relationship as I enjoyed solo hobbies such as gym, writing, reading, gaming and Lego and feel pretty crowded and overwhelmed with a constant presence when I'm not working (exes have all worked full time also). I feel like I've lost my identity a little bit, and my freedom.

I have really struggled with his desire for a deep level of communication and this has led us to almost breaking point many, many times. He says I don't communicate at all. I've never known I've had issues with this in the past and he says its because I've chosen weak men who didn't care about me on a deep level. I just don't really have much to say beyond 'I'm down today' 'I feel a bit sad'. I do bottle things up that annoy me then explode and I'll admit that but it's very hard to just change which he's said he accepts.

The most recent breaking point has come after me discovering I'm almost certainly a Dismissive Avoidant. It has almost broken me. I don't know how to deal with it, I'm in the UK and I can't afford therapy right now. There doesn't seem to be a handbook on how to 'fix' it. I never knew my dad, he used my mum as an escape from a family she never knew he had then dumped her and went back to them when she found out she was pregnant. He never admitted I was his and I never met him, we found out he was dead through a newspaper obit. Obviously the issues with my cheating ex and others must have had an impact on me that I've just never realised.

On top of this, I'm also going through chemo and other treatment for breast cancer, I've already lost a breast and am currently losing my hair plus I've struggled with my weight and fitness which has me feeling all kinds of bad about myself.

I saw my partner Friday through Monday night last week and was pretty ill and down (chemo and forced menopause) He was angling to do the same every week but I honestly can't cope with him right now. He's been really pretty awful in places throughout my shitty cancer journey, he's accused me of using it as a shield to justify my behaviour and I'll admit I have lashed out and said some nasty things too.

I just don't think I feel the same about him and I know and have told him I don't want to live with him. He has a dog (I have a cat) and his ADHD means the division of cleaning just doesn't happen. We also don't really do anything except walk the dog around the same park. We can't even agree on movies. He doesn't game. Plus I feel I can't be myself around him. If I want to slob and watch shit films I don't feel I can. He constantly tells me he adores me and would marry me tomorrow but then he can be super nasty. He once said (soon after my cancer diagnosis) that he wished I'd fall down the stairs. He hid my phone last week because I refused to discuss our relationship (its all he wants to talk about and honestly my chemo brain needs a break) and also ripped the duvet off me and wouldn't let me leave the bedroom one night after an argument to show me what its like to not get what you want and be abused, as he regularly tells me I do this to him.

I've wanted to break up many times because I feel we have so little in common as well as the constant arguments and he keeps telling me I'm 'not trying' but begs me to let him be in my life in any capacity, even suggesting he would just be there to support me during cancer as a friend. Yet we slip back in to old behaviours and he has me believing its entirely my fault. He's said he knows how not to trigger my behaviours but still does. He's said I use him as a toy and what he's given up for this relationship (as in not being able to work as a motorbike mechanic or ride bikes etc because he's neither at his own place or mine permanently)

I just don't know if it's my DA deliberately sabotaging the relationship or if it's just not working for other reasons. I honestly feel nothing but relief in the thought of not being with him again but that's classic DA isn't it? The fact I have cancer and look and feel completely different doesn't seem to factor into the equation and I feel like I use it as an excuse to not see him all the time. I'm so confused and don't know what to do for the best. Any advice gratefully received.