Exactly. God knows the hardness of the human heart. Remember, the Law is perfect.
When you discuss marriage between 2 believers, it is different. But when one is not a Christian, and is bent on destroying the other, allowances are made - see 1 Cor 7.
Also, note that Jesus DID allow for divorce for adultery - once the bond is severed, divorce is allowed.
I’m not praising divorce, but it isn’t quite a “no divorce” situation.
There is only one sin that is not forgivable and divorce ain't it.