In most divorces, we have to call witnesses to finalize the divorce. Two witnesses are needed and if you are called as a witness, it is because you are a witness to the fact that the parties have lived separate and apart for a certain period of time.
In your testimony, we will ask you these questions: do you know the parties? Do you know if the parties have been separated for six months / a year?
Then, an important question you will be asked is: “would you know if the parties have gotten back together?” The answer should be that yes, you would know. You should be able to say that you see one of them regularly enough that you would know if the two of them were living together.
That is called the “foundation.” It means, we are showing that you are in a position to answer the important question: “have they actually gotten back together as husband and wife?” Hopefully the answer to that question is “no,” otherwise the divorce is not happening.