Please don't think I was specifically arguing a point or arguing against one of your points, or reading into what you wrote specifically. I was merely
sharing because what you wrote touched me. (It might not have come out that way in my writing, though, I admit.) And that all was mostly triggered by the line that I quoted in my earlier post.
Now, your situation is exceptional and something like that can't be assumed when speaking generally. It's similar to your spouse getting seriously ill. From being a husband or a parent it turns a relationship or a parenthood partly into a special case of taking full-time care of a very ill person. So in that case we're not strictly talking about only parenthood anymore. It's partly patient care, not just parenthood.
However, I think I still carry the same opinion: taking care of yourself first is especially important in a situation like yours where you might have to take care of someone into his adulthood.
A person can only give as much as he's been able to receive himself. If you don't put yourself first ever then eventually you imperatively have no chance of giving anything to your son or anyone else in the long run. (You might be able to trick it for years in the beginning, though.) It's like you have to stop to fill up the gas tank while driving a long distance. Otherwise you just can't do it at all.
I also want to point out that I was not advocating taking a long vacation with your wife just like that: putting yourself or your relationship first doesn't mean leaving your kids in abandon. (Or maybe, naively, for some people, it means just that but it wasn't what I was thinking.) I did write that parents can't just do whatever they feel they need to do and ignore the kids. I'll try to reiterate my viewpoint.
What I mean by putting yourself or your marriage first is that in the worst cases, you do just that, but only in the worst case. If it's not the worst case you will have some energy left for others, too.
For example, if you're truly out of the game, you must be able to say to your wife "Honey, now I just can not do this anymore. I need a weekend alone at the cottage or with my friends or I'll just simply go mad somehow and I don't have anything left for myself or our marriage. I'm sorry I can't be more flexible now and you'll have to take care of all things but I'm so out of everything now that I just can't. I'll be back—but not today."
Or if you're exhausted with your kids, you're going to have to be able to say: "Listen guys, we're so worn out of everything that we're going to have to postpone the beach trip we planned with you and instead send you off to your grandparents for the weekend. You see, we need some adult time alone with your mother so that we'll have time to enjoy ourselves too instead of always working and taking care of others. If we didn't do that, we'd become quite uptight and just plain angry at everything, and you wouldn't like that either. So, we're going to have to take you out to the beach sometime later and you're going to go visit your grandparents for the weekend."
Of course you have the responsibility for your kids and you can't drop that. But kids can survive a night without a proper meal. They will live even if they don't have clean clothes for few days. And they can't always enjoy the privilege of your full presence. Doing such things repeatedly would be detrimental to their childhood but in the worst case it's better for them to suffer little than see their parents gradually losing their grasp on life.