Ugh. Daggers in the heart. How do you guys find peace when things feel so, so bleak? I don't know how spiritual you guys are, but when I pray and meditate, it's pretty much immediately better. Don't get me wrong, these soul crushing moments come fast and furious, but then...they're done. Is that your experience?
Its the most difficult thing there is - and makes the death of the marriage look like a walk in the park. Prayer does help. But what helps the most are the kids themselves. Their hugs, telling me that they love me, etc. I never show them what it does to me - they have enough on their plate. I know, kids need to know that its ok to show feelings and all, but some things are better left kept in check.
Yes, you need to be strong for them. They don't need the extra burden. And they'll look back remembering and appreciating your strength and dignity.