The moral of making this about me: We all have highly personalized comfort levels and pain tolerances, and no one phrase is going to capture the right threshold for everyone.
I'm with you on the can't-live-without standard, seems a bit much, and prefer the more temperate "Marry someone you don't want to live without," or even the romantic realist's "Marry someone you can't envision life without."
The closest I've come to a universal standard came from Iris Murdoch: "One should never commit oneself until one is amazed at one's luck."
Question: Is it within the range of normal to feel pretty constant low-grade irritation/anger with a spouse of more than a decade? I definitely love him, and he's a good dad to our three kids (two elementary age and one toddler), but I often find myself annoyed or angry with him. Maybe this is as good as your average marriage gets at this stage of life?
Answer: Never ignore anger. It rarely goes away on its own and instead usually metastasizes.
That said, you're right to look to your stage of life - small kids can grind you down - and your own general well-being. Are you depressed, exhausted, overextended? Any of these can emerge as irritation with the people nearest at hand, and since a lot of parents feel uncomfortable getting irritated with their kids, they funnel bad feelings into the nearest adult.
It's crucial to pinpoint the source of your irritation, and the best way to do that is to work what might be a small miracle: Clear a little time for yourself so you can think straight. Get that time by admitting to your husband that you've been feeling irritable a lot and you suspect you're overextended, and you want to deal with it now before you become a galloping (meanie).
If/when you get this time, use it to get out unencumbered, see a friend, even just take a walk. Get your circulation going in ways you've let slide. Don't force your thoughts; let ideas come when they come.
When they do, talk to a trusted friend or, if they're all too close to your family, a therapist - whoever helps you think clearly and speak freely.
What comes next depends on what you identify as the root problem, but I suspect just getting a little distance from your routine will not only clarify your thinking but also reduce your stress appreciably.
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