Families are designed by God to endure forever in their patriarchal structure. Our worthiness in this life weighs heavily on whether or not we will maintain our place in the eternal family of God.
Of course there are better higher states of blessing based on works in this life and our intentions while performing them. It is scripture and it's a basic of life. We feel good while executing good works. That is a blessing upon us and those we serve. All that adds to our book when we are judged.
According to scripture the people of God are to be joint-heirs with Jesus Christ. Yes, upon our worthiness there is no limit to the blessings and potential of our being. All things are granted through Him according to our faithfulness. When we enter into a promise or covenant with God he is bound to uphold that promise. It's us that have the agency to break such promises.
Eternal life of joy and happiness also encompasses eternal posterity. That is joy! If found worthy a husband and wife, solemnly bound, can receive the blessings of eternal joy and happiness with an endless posterity. Joy is not eating grapes and being fanned by servants in the heavens. Joy is work and the fruits of that work. It is receiving and nurturing the blessings of eternal life through endless learning of knowledge as well as posterity.
It's really not so hard to understand. As man now is, God once was. As God now is, man may become. God is perfected and has endured and conquered his own temptations in His own mortality. Isn't that awesome! To know that He has gone through what we now live - it's just like fatherhood here in life. We often don't appreciate our parents until we become such and have been seasoned. Then we love them all the more because we then know what they suffered.