A shared life improves when small concerns can be raised before they need a serious tone.

If mentioning something requires a serious conversation, most things stay unmentioned. The bar rises until only major grievances qualify, and by the time an issue is large enough to justify that tone, it has been carried for months and grown a history. What keeps a household light is a low threshold for saying things while they are still small enough to say casually.

Raise something minor this week in an ordinary voice, and let it stay minor. Making it normal for either of you to mention a small thing matters more than any small thing you mention.