Over years- we age. Our skin changes- as does all the inside bits. But each day- say over a 15 year period, the changes are oh-so slight, we do not really 'feel' the change.
As an alcoholic (of which I was the one who destroyed my family) my drinking slowly go more out of control over years...day by day. So the stress my ex felt- day by day was slow to build up- and on a daily basis- turns horrible circumstances into that we know and understand.
Humans do not like change. Even if the change is for the better- we tend to relate to what we know. I came from an alcoholic family of origin with a huge amount of dysfunction- but this was normal to me, and so when I became an adult- my distorted view of the world- made me think anything outside my negative self loathing and stuff- was natural and normal.
To break out of this miasma of feeling an offence to the universe for me is hard- and I resist, because the negative stuff is all I have known.
I think this is why people stay together- they change but do not realise it, they become so accustomed to feeling like crap and over years- it becomes harder and harder.
My prayers and support to you.