Another way to look at it, is that a life is something that, ideally, should be spent, and poured out completely, to achieve some goal, and that lucky are the people who manage to find their goal that’s worth pouring out their entire life for.
As an example, let me tell you a little about the smartest person I know. I tend to hang out with pretty smart people, so it should be no surprise that this guy is absolutely brilliant. He has an idea, or a set of interlocked ideas if you prefer to think of it that way, that just might lead to an understanding of quantum gravity. Now, please understand me, here: When I say “might”, I mean that my estimate is that there’s, at best, a 10% chance that it might pan out, and a 90% chance that it’ll lead to absolutely nothing.
But this guy is pouring out his whole life in pursuit of this idea. If it works, of course, he’ll become one of the great men of history. But if (as is much more likely) it doesn’t, he’s going to amount to nothing much, because he’s putting everything he has into it.
On the one hand, this has been very painful to me, to watch a friend of mine set off down a path that will likely lead to self-destruction. But on the other hand, I can’t say that he’s wrong. Because quantum gravity is big enough that, I think, that even a 10% chance of it is worth that price. And ultimately, it doesn’t even matter what I think, because he’s the only one who can decide what it’s worth.
To bring this back to the OP, maybe, if one’s spouse is great enough (however one mentions greatness, and everyone has to decide that for themselves), it is worth devoting one’s entire life to supporting that spouse. And that’s a decision that we can’t make for anyone else.