I think posters saying the OP’s husband is unreasonable need to give their heads a wobble. The man is dying. He knows it. We know nothing of how recent the diagnosis was made or how imminent it is. How would you all feel if you were suddenly faced with your own mortality ? No, shouting and bad temper are not the ideal, but they are understandable in this situation. OP shouldn’t have been driven to the point where she wants to abandon her DH and her son in the first place. That’s not her failure, it’s the consequence of a broken system and the resulting lack of support.
And to those of you happily recommending she seek respite or hospice care, get real. I’m 66 and physically disabled. My partner is a double amputee and is in heart failure. My 94 year old mother who has severe dementia is living with us. I have just been diagnosed with breast cancer. I’ve been at the breaking point OP is experiencing now, having had two lots of surgery, including mastectomy and having had to come out of hospital after day surgeries and be thrown back into caring duties almost immediately.
I am unable to access respite because all the care homes in the area have either been shut down or are acting as halfway houses between hospital and home for those bed blocking because they’re not ready to go home. My GP helps with medication to keep mum calm, and monitors my partners’ condition but I am still expected to do basic obs every day including blood pressure, and sugar, and report them in daily - as well as ferrying him round to various appointments, as they do not consider any of us to be housebound. I have a little family help from my partners’ daughter, and a private carer coming in for mum - who thankfully, has become a good friend and does a lot more out of kindness than I actually pay her for. Without her and support from MacMillan cancer services, I would have gone under.
Social services care was an expensive waste of money - there were supposed to be four calls a day for mum. In reality it was three, and sometimes two, because the morning call was non existent and by the time they turned up at lunch time I had mostly struggled to get her ready for the day myself. The evening call to put her to bed was supposed to be 9pm, but in reality it was mostly 5.30-6pm because they were so short staffed. When they did turn up they did the bare minimum and if a morning call was made, they wouldn’t shower or wash her without her express permission - which she was unable to give. Total waste of time and virtually wiped out her income.
OP my heart totally goes out to you because the support you need is barely there. In reality your DH won’t get respite care until he can’t manage his pain or other symptoms are overwhelming. My first port of call in your place would be Social Services to get a carers assessment - this is not for your husband or son, but assesses your own needs as sole carer to both of them. I would also get on to MacMillan and explain the situation to them - do you have a dedicated nursing team at MacMillan for support ? If so use it. Don’t be embarrassed and don’t hold anything back. Then I would contact your GP. Make an appointment to talk through the difficulties you have and ask them to signpost you to support. Many surgeries have services available to support carers in house, so may be worth enquiring along those lines.
You’re at breaking point and sadly this is common, but I’ve learned the hard way that the minute you accept responsibility, you will be left to cope. You are also dealing with anticipatory grief because of your DH’s terminal diagnosis, and you need help to process that, as it sounds as though it’s adding to the very heavy stress load you’re carrying. Can you ask your GP for a talking therapy referral on an urgent basis ? It also sounds as though your DH is struggling to accept what’s happening to him and is taking it out on all of you. It’s not right - it’s understandable, but he needs help to process his own situation. MacMillan should be able to provide some support with this.
I’m so sorry I can’t offer any better advice but I just wanted to let you know you’re not alone, and to stress how important it is to seek help and not minimise what’s happening. Unpaid carers save the tax payer a fortune and help and support should be there to avoid precisely the kind of situation you find yourself in now.
Edited to say that the Maggies’ organisation is really good. OP, if you contact MacMillan and ask where your nearest Maggies’ is they should be able to help you access some support, and there will be people there in similar situations to your own, so maybe a valuable opportunity to talk things over too.