Paul Tripp describes where the biggest battles of marriage are fought

I continue to recommend, What Did You Expect?: Redeeming the Realities of Marriage.  Notice that sin is antisocial:

I have said this and will continue to return to it throughout this book: the big battles in marriage are not the ones you fight with your spouse.  No, the big battles are the ones being fought in your heart.  All of the horizontal skirmishes between a husband wife are the result of this deeper battle.  Remember, there is still sin remaining in your heart, and the DNA of selfishness.  Since since in its fundamental form is selfish, then sin is essentially antisocial.  This means that you and I must recognize there is something that still lurks inside us that is destructive to marriage.

See also this quote found in the same book, as well as this one about too many of us trying to have “hundred dollar conversations in dime moments.”