This answer is not intended to provide you with specific legal advice, and it is not intended to create any attorney-client relationship.
If a couple in Georgia owns a house or other piece of Georgia real estate under a deed which lists both of their names along with the words "as joint tenants," or "as joint tenants with rights of survivorship," then the ownership of that piece of real estate will automatically pass to the surviving member of the couple upon the death of the first member to die. If the deed to the real estate does not contain the words "joint tenants," "joint tenants with rights of survivorship," or very similar language which makes clear that the property is held with rights of survivorship, however, then the interest held by the first person to die will remain in his or her probate estate, where it will have to pass through his or her Will or by intestacy. Therefore, the language in the deed can be quite critical where avoiding probate is the intent.
Ensuring that the property avoids probate at either person's death even if death happens simultaneously or very close together is more difficult. What I would normally recommend in that case is for the couple to create revocable living trusts, one for each of them, and to have the revocable living trusts become the owners of the real estate. Assuming they each want to have control and they each want the other in full control after the first person's death, they can each be co-trustees of the other's revocable trust. Assets which are owned by a trust at the death of the person who created the trust pass according to the trust's terms. Assuming that the trust does not distribute the assets back to that person's probate estate, the assets owned by the trust should not have to pass through probate or an estate administration. The process of having someone's Will admitted to probate in Georgia gives that person's heirs (which would include children as well as a spouse, if that person had a spouse and one or more children) an opportunity to challenge the person's Will. While a trust can be challenged under Georgia law, it is more difficult to challenge a trust than to challenge a Will. Therefore, while using revocable trusts does not absolutely ensure that no contest or challenge to the estate distribution plan will be brought, it can help to reduce the possibility that a challenge will be brought by raising the level of difficulty for someone who wants to do so.
If the overall plan is for the surviving spouse's estate plan to provide for the distribution of the entire parcel of real estate, then you could have each revocable trust provide that any interest in that parcel which the trust holds at the first person's death would be distributed to the survivor's revocable trust. That should keep the property out of both people's probate estates even if both deaths occur close together.
I would very strongly recommend that you seek the help of an experienced estate planning attorney to prepare your estate planning documents and give you advice on how to own your assets so that the plan you want is the plan which is actually carried out. The attorney should take into consideration the overall situation and help you address the number of issues which tend to exist in a second-marriage situation.