In the case of a married filing jointly (one spouse didn't work), does the tax refund belong equally to both spouses? There are 2 children claimed as well (the kids are ours together).

Thank you.

II belongs jointly to the people filing the return.

What would be the penalty if one spouse took all the money? Is this a crime?

It depends on the circumstances. Since the money belongs to the family, I don't see a crime if one spouse uses it.

However, if there is a pending divorce, it could become an issue in the divorce.

We're going through a rough patch, separation and divorce has been discussed. He insists the money is all his, it's going into his bank account so it's not like I could go down there and take my half. I'd just like to know if it would be a crime for him to block/refuse access to my portion or steal it altogether.

No its not a criminal offense. It is a matter for distribtuiion of assets in a divorce.

Nothing criminal, morally it is the family, and this can be one of the issues sued for in divorce court