Matthew has an important piece of information that Mark misses.
Matthew 19:9
And I say unto you, Whosoever shall put away his wife, EXCEPT it be for FORNICATION, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.
Hosea 1:2
When the LORD first spoke through Hosea, the LORD said to Hosea, "Go, take to yourself a wife of harlotry and have children of harlotry; for the land commits flagrant harlotry, forsaking the LORD."
God did divorce the Northern Kingdom of Israel.
Hosea 1:6-9
Then she conceived again and gave birth to a daughter. And the LORD said to him, "Name her Lo-ruhamah, for I will no longer have compassion on the house of Israel, that I would ever forgive them.
"But I will have compassion on the house of Judah and deliver them by the LORD their God, and will not deliver them by bow, sword, battle, horses or horsemen."
When she had weaned Lo-ruhamah, she conceived and gave birth to a son.
And the LORD said, "Name him Lo-ammi, for you are not My people and I am not your God."
But as always He turns our failures into success.
The Torah says that husband can not remarry his divorced wife.
Deuteronomy 24:1-4
When a man takes a wife and marries her, and it happens that she finds no favor in his eyes because he has found some indecency in her, and he writes her a certificate of divorce and puts it in her hand and sends her out from his house,
and she leaves his house and goes and becomes another man's wife,
and if the latter husband turns against her and writes her a certificate of divorce and puts it in her hand and sends her out of his house, or if the latter husband dies who took her to be his wife,
then her former husband who sent her away is not allowed to take her again to be his wife, since she has been defiled; for that is an abomination before the LORD, and you shall not bring sin on the land which the LORD your God gives you as an inheritance.
That is why the bridegroom had to die. After He had resurrected that law does not apply any more and now He can take her back. Just like Peter told us quoting Hosea 1:6-9.
1 Peter 2:10
for you once were NOT A PEOPLE, but now you are THE PEOPLE OF GOD; you had NOT RECEIVED MERCY, but now you have RECEIVED MERCY.
Which agrees with what Hosea prophesied himself just after God divorced Israel.
Hosea 1:10-11
Yet the number of the sons of Israel Will be like the sand of the sea, Which cannot be measured or numbered; And in the place Where it is said to them, "You are not My people," It will be said to them, "You are the sons of the living God."
And the sons of Judah and the sons of Israel will be gathered together, And they will appoint for themselves one leader, And they will go up from the land, For great will be the day of Jezreel.
Now we are only waiting for the sons of Israel (sons of nations that is Christians) and Jews to be gathered together under one leader, Jesus our bridegroom.