not in a single HN comment, no. I can't compress a lifetime of experience (second-hand) into the amount of text I'm willing to write right now with fidelity.
Reading through my HN comment history, and my wife's HN comment history, can give you some insight into what we learned from our grandparents (hers also had lifelong marriages.) Reading through the books published by the mathematicians I mentioned, and digging through the statistics I posted, are additional methods you can use to gain insight into what works. Talking to people you know who've had long and successful marriages (ie, not my grandparents, but yours) can help.
Reading through my HN comment history, and my wife's HN comment history, can give you some insight into what we learned from our grandparents (hers also had lifelong marriages.) Reading through the books published by the mathematicians I mentioned, and digging through the statistics I posted, are additional methods you can use to gain insight into what works. Talking to people you know who've had long and successful marriages (ie, not my grandparents, but yours) can help.