Hi, everybody's situation is unique, so whilst I know our marriages will be totally different, I've given detail to explain what changed in me- ultimately I realised how much I love DH and want our marriage to work, so I realised I wanted to focus on making the future right and not going over what had gone wrong.
So I think at this point in my post, ask yourself if you do love your DH and want to be with him if things could be different. (If you don't, I honestly wouldn't bother reading anymore if I was you, as its long, rambling and utterly boring if of no relevance 
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me and DH have been together 20 years, married for 10. 3 dcs (9,7 and 20months, plus amiscarriage in between dc2&3). I have an elderly parent with advanced Alzheimer's who i was helping look after at home until last year too. In a nutshell, from my point of view, I felt DH didn't give me any support through the miscarriage or caring for my dad and watching him deteriorate in front of me. I felt he made no effort with anything and didn't listen to anything I said. We were always arguing over the same issues. Not for a minute am I suggesting this is totally accurate, just why we'd got to the point we had.
A few months ago I realised I could no longer cope with the constant anger, and used to dread him coming home. And I realised that ultimately I love him. And the anger just disappeared. I'm not saying it's that easy, but I realised that all the things I was angry about were in the past. And continuing to be angry wasn't helping me move forward. I still needed to understand what had happened for me to feel unsupported, but I wanted things to work if they possibly could and needed to see where we'd both gone wrong. Once I'd stopped being angry, DH openly admitted he felt he'd been a crap husband, had totally let me down as didn't know how to support me, and felt I deserved much better. in fact, DH struggled to talk for a while as he couldn't believe I had just moved on and left everything in the past where it rightly should be.
It might sound like nothing has been resolved, but I do think it comes down to whether you still love each other and want a future together. I realised being angry / hurt / going over stuff again and again wasn't getting anywhere and realised one of us had to change to enable 'us' to change. So I wondered what would happen if I just looked from a point of view of moving forward and building a positive relationship (a bit like the toddler stage, praise the good behaviour, ignore the bad in a way, 
) except this wasn't ignoring 'bad' behaviour as we both had valid points of view about what happened, but it's looking to move forward and realise to understand each other we need to do make changes in the way we behave / communicate. If I need support I need to say it right from the start instead of being stoic, battling on then feeling let down when the burden is too big.
I know I'm waffling, I'm struggling to explain, but keep trying, as I feel we've made huge progress over the last few months from where we were at. For us to move forward, it's been a case of letting go of the past, but recognising changes that need to be made, which acknowledge where / why things went wrong without rehashing any old arguments.
If nothing else, I hope to receive the MN award for most boring, rambling, unnecessarily long post ever. I feel I've said the same thing over and over but in a slightly different way each time. Wish I could be one of these posters who passed on pearls of wisdom in a succinct, intelligent manner 
good luck with moving forward, whatever it is you want your future to be.
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