Take the emotions out of it and start looking at this thing as objectively and pragmatically as possible.
Do what it takes to stop focusing on what's wrong and start feeling good and human and happy - regardless of what's going on around you. Challenge your normal. Face some of your fears.
Get a goal - I'm not really good at all the organization involved in these parts but I've always had a big goal (which actually had nothing to do with my M) - It's been my distant beacon when things were extra rough.
Hang in there. There is no magic wand and you gotta override the huge desire sometimes to just give up.
The old screen that used to show before you got here - right off said "they know this isn't the place to come complain about their spouse" - yet so many people do just that. I find that a great many people come here as another outlet to pour out their emotions and I think most of us who try to turn it toward Michele's stuff have been rebuked pretty hard several times an then chided by others. Because they're still stuck in that mindset of the psychological standard - THAT IS NOT MICHELE'S STYLE!!! And I'm not speaking for the lady one bit - I'm just familiar with her work and have seen her in action here on the boards on occasion. She's told people to do things that have made my jaw drop! But I've tried a few of those very things and they really do work. She's on to something people and she's providing you all tools and an outlet to do it.
I know just how hard it is and can be. I understand the need for support and venting and tears and all that other stuff - just more people need to understand that a little of that goes a LONG way and too much/habitual any of it is just more of the same and gets in the way of getting anywhere or making change. For many of us, it's the busy work we do because we don't want to do the real work. And it's socially acceptable - but it doesn't make it right or good.
So get strong (and don't feel bad or guilty for it). Get happy as much as possible. And most importantly (to me) - pretend you are an outsider in this and the situation is happening to two other people that you don't know.
You will not fail if you do this stuff. Even if your R ends - you will not fail and your SO and any kids will most likely be better off as well, somehow. Really - any of us who have truly gotten to that point will tell you that. It doesn't mean we still don't cry or get angry or fall backward a bit sometimes - it just means that we aren't captive to it - we choose to live instead and have developed the skills and new habits to make it an opitmal choice.