Couple Plan is a weekly or yearly auto-renewable subscription. There is no free trial. The price is shown by Apple before you confirm. Family Sharing is off.
One Couple Plan can cover both connected LovePact accounts. Only one of you needs to subscribe. The subscription belongs to the Apple ID that bought it. It is not transferred to the other person.
If you already subscribed and coverage is missing, open Settings, Couple Plan, and tap Restore Purchases after you are signed in and connected. Restore checks the Apple purchase for this account. It does not move a subscription onto your partner’s account.
If the purchase sheet does not appear or the price does not load, check your network and Apple ID, then try again. You are not charged unless you confirm a purchase with Apple.