does a judgment against decedent's estate affect real estate owned with spouse prior to death?

Answer 1

Depends on the state. Most state allow taking of property as Joint tenants with right of survivorship or tenants by the entirety, so that the death of one allows the other to take title without passing thru probate; assuming you took title that way.
In that case the judgement is the property of the estate and not the problem of the title holder.

Some states don't. Your atty can tell you as can the county clerk's office

In any case, the judgement will need to be settled from his estate;

Answer 2

The first question is whether or not the property automatically passed to the spouse upon death. If so, then judgements against the estate can't touch it.

If that's not the case, then the next question is whether or not there was a Will. If a Will gave the spouse a specific devise of the property, AND there are sufficient other assets to pay the judgement, then it will be paid from the "residue" of the estate.

If there was no Will or no such specific devise, or the residue is insufficient, then it is possible that the judgement can impair the real property.