Husband and wife for hundreds of times of consecutive rebirth. How?

I don't think everyone will reborn when he or she dies. As far as i know, there are also many places like heavens and hells, not just this human life. For couples to meet again in later lives, they have to do good deeds together or say prayers. That shows great bond between them. But it also does not make sure to be born again together in consecutive life.

Time is different in the heaven realms and animal realms. This is a Buddhist cosmological fact that I can reference the Buddhist scholar Brian Ruhe's books and youtube videos for... and then can find which Theravadin sutra talks about it (it should be the one about The Thirty-One Planes of Existence).

Compared to the human plane, time is faster in the lower planes and much slower in the higher planes (1 day in the heavenly realm is equal to thousands of days in the human [or was it a million?]).

Anyway, to answer your question, that is how; one partner may have spent some time in animal realm while the other may have spent some time in heaven and then they both sank to human realm at same time, etc.

This cycle of break-up and getting back together happened again and again hundreds of times.

[Sounds like my last relationship.]

I can give you a precise answer if you have a textual reference where such a story came from.

If such a story was from gossip alone, then you may know that it came from the Buddhist cosmological time difference fact that I stated above.

Usually wife is younger than husband. So they do not need to die at the same time to be marry on the next life. The real difficult part of here is to born in same world (for example both become humans) in a manner that they meet again.

No one can control this and no one can guarantee that they will meet again. (But there can be people who can tell whether they are going to meet again or not.) It's Karma which going to decide all.

For your reference, this is how rebirth happens as of my understanding. I am calling 'thought' a single 'Sitha'. Correct word is not thought. But I don't know what it is.

When a person is about to die, one of three things comes to his mind.

1. 'Karma Nimiththa' This is either tools, people or animals, helped to do the Karma caused to next life.
2. 'Gathi nimiththa' This is something related to next life he is about to reborn.
3. 'Karma' This is Karma itself, which caused to next life.

Once this thought comes, he begins to think in that direction. When the last thought of this life ends, the next thought of the same thought generation will generate on the body of the new life. This is saying person go to a new life. There is no intermediate body and nothing goes to next life from this life. Just a connection between the generation of thoughts.

Husband and wife for hundreds of times of consecutive rebirth. How?

In AN 4:55 - The Same in Living, the Buddha visits a married couple in their residence. Here he is given alms food whereafter he gives a teaching to the householders.

Both householdes, Nakulapitā and Nakulamātā, asks the Buddha how they can remain together in this life and meet and be together in future lives as well.

The Buddha teaches: “Householders, if both husband and wife wish to see one another not only in this present life but also in future lives, they should have the same faith, the same virtuous behavior, the same generosity, and the same wisdom. Then they will see one another not only in this present life but also in future lives.”

Below is the quoted sutta.

55. The Same in Living (1)

On one occasion the Blessed One was dwelling among the Bhaggas in Suṃsumāragira in the deer park at Bhesakalā Grove. Then, in the morning, the Blessed One dressed, took his bowl and robe, and went to the residence of the householder Nakulapitā, where he sat down in the prepared seat. Then the householder Nakulapitā and the housewife Nakulamātā approached the Blessed One, paid homage to him, and sat down to one side. The householder Nakulapitā then said to the Blessed One:

“Bhante, since I was young, when the young girl Nakulamātā was given to me in marriage, I do not recall ever transgressing against her even in thought, much less by deed. We wish, Bhante, to see one another not only in this present life but also in future lives.”

The housewife Nakulamātā in turn said to the Blessed One: “Bhante, since I was a young girl given to the young householder Nakulapitā in marriage, I do not recall ever transgressing against him even in thought, much less by deed. We wish, Bhante, to see one another not only in this present life but also in future lives.”

“Householders, if both husband and wife wish to see one another not only in this present life but also in future lives, they should have the same faith, the same virtuous behavior, the same generosity, and the same wisdom. Then they will see one another not only in this present life but also in future lives.”

Both husband and wife are endowed with faith, charitable and self-controlled, living their lives righteously, addressing each other with pleasant words,

Then many benefits accrue to them and they dwell at ease. Their enemies are saddened when both are the same in virtue.

Having practiced the Dhamma here, the same in virtuous behavior and observances, delighting after death in a deva world, they rejoice, enjoying sensual pleasures.