I love my husband more than I love my children (2004)
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The marriage must always be number one. That's not such a distinct thing from the welfare of the children, though; the lives of all family members are inextricable. Neither the husband nor the wife are going to be pleased and say the marriage is going fine when the prosperity of one or more of the children is in jeopardy.
"The children" and "the marriage" are not really separable. They are two fully blended parts of the same thing, "the family". Spouses and children are not competitors; they're collaborators. Any action on one part is going to spread out over the others.
Having said this, my brother married a seemingly perfect partner. They played squash/tennis, went out on a Friday night date each week, played bridge with others, loved crosswords together, and still ended up divorced 10 years and 3 kids later. Sigh.