Many Protestant exegetes argue that God simply failed to prohibit sinful divorce rather than establishing a permission to divorce under certainl circumstances. They argue that God simply mandated that such sinful divorces be documented officially.
This argument is unconvincing for several reasons, not least because God himself divorces in exactly that way.
I think there are times when not divorcing would be the wrong thing to do. If an unrepentant spouse keeps breaking the marriage vows in an egregious way, claiming it would be wrong for the other spouse to leave, I think wise elders should take church discipline all the way if the offender is a church member and should encourage the offended spouse to leave. To stay when there’s a way out is to say amen to the offender’s perversion of marriage, which is a perversion of the image of God.
There’s a well-known kook who turns that argument on his head — God ONLY made the divorce laws so He could have a precedent for his dealings with Israel, they don’t actually apply to human relationships, where divorce is absolutely forbidden (or “impossible,” in his favored parlance.) So in essence, God makes fake laws for people so He can have a reason to do what He wants., but people aren’t actually allowed to use those laws. I can’t think of anything that qualifies for “making God a liar” more than that.
And following Valerie, in some situations, permitting divorce seems to be a matter of mercy and justice to the wronged party(ies), not just a way out of an uncomfortable situation. Telling a spouse and kids that their circumstances are forever at the mercy of someone who neglects and/or violates his duties as a spouse and parent in every possible way doesn’t merely seem “mean” from a human standpoint, but seems to violate the general thread of biblical justice.