The phone is the third wheel in your relationship. Third Wheel kicks it out of bed.
You each pick the apps that steal your evenings. At bedtime one of you taps the heart and both phones go quiet until morning. The only way out early is to ask.
Android first, iPhone next. One email when it launches, nothing else.
$4.99 once. Your partner gets it free.
One of you buys it. The other joins with your code. No subscription, no third wheel.
It's not a parental control and it's not one of you policing the other. Both phones lock or neither does. Neither of you can see the other's app list. And there's always an emergency unlock, because life happens; it just gets recorded.