I'm glad that you calmed down op. It isn't great to respond in anger but it is clear that those who are calling you unreasonable are either those who would be cheeky with this sort of take but no give or have been programmed through their own parents to find this sort of thing unreasonable.
I few years ago I may have been one of them and still struggle with getting boundaries and healthy relationships expectations right but it is clear that we are as a society facing an increasing awareness of how messed up certain behaviour has shifted and negative it is.
You are totally reasonable - it is clear that this is built on years of pain and is the final straw that broke the camels back rather than any spoilt notion your part. You can only learn from this that they are not reliable in any way and find coping methods on how to proceed.
My dad is the same and went nuclear when he found out me and my sister weren't happy as his wife, our aunt, was making our life hell. My sister is no contact with him not long after that for over 5 years now while I have my own methods, any living far away, of coping with this sort of behaviour.
For me it took him threatening my partner with a huge knife over goats cheese to realise that my sense of a healthy relationship was messed up. Just be thankful you realised it now before it got to anything like that.
It is so hard being a parent with no close support network, and I say this even with my husband being here. Those who get those precious times away don't realise just the difference it makes or just how lucky. How many of those calling you unreasonable have been "well we never ask for help on a x day as that's their day" clearly do get some nights off other times.
I would suggest talking to a mental health professional though - it sounds like you are coming out of that fog and I know from personal experience that it will be a painful journey ahead and they will be able to give you great tools to help cope with this realisation and building healthy boundaries.
There was one where I was that even had a crèche and was art based for mums. Others have been one to one and helped create a plan of action for dealing with this sort of thing.
I really hope you have a good birthday. You have in some way been given an important gift of realisation and the start of a journey that will make you a happier and healthier person in the long run.
I hope you can find some one else who might be able to help, but I know how difficult that can be.