Right I have something I hope will be more useful.
I think there are some issues where you can agree to disagree and you can get passed it and just not really talk about it.
Obviously things like Brexit and Anti-Vaxx - things like that are very divisive, you would have to have a very strong marriage or relationship to be able to rise above it and agree to disagree.
Something that is fundamental, such as religion, something very core to the way you see others, yourself etc would understandably be a reason to separate for irreconcilable differences.
I know I have changed a lot since I came to Mumsnet as a new mum and to this board. My DH wasn't keen on those changes and we have broadly agreed not to discuss Self ID (though he agrees he doesn't see it as a threat or big deal) but there are times that we do, we sort of have to as he is my best friend and it affects me deeply. We should be able to discuss our worries and fears for the future as well as all the hopes. If not then I don't really know if I could keep that all in. Not the big stuff.
It's obviously very personal Sapphos - for me I know I would leave if I found him cross dressing, became a Scientologist, started exploiting vulnerable women via porn or prostitution. There are just some deal breakers in life. I could forgive gambling, heavy drinking and other things I wouldn't consider as serious.
I suppose what I'm saying is it depends on whether your think you can find a middle ground or manage to go on if you can't.
If, in our discussions around Self ID I knew my DH was fully on board with TWAW, I would seek counselling and through that I would find out whether there was any understanding and support for my position or not.