There is an argument among the Rishonim mediaeval authorities what is the law of a נערה בתולה מאורסה שזינתה a girl [12 years old to 12.5] that is in this intermediate state between betrothal and marriage who has had sexual relations with another person besides her husband. It is the usual case of an argument between Tosphot and the Rambam. [Betrothal is marriage, but before the chupa.]

Just to be clear- a married woman who has sex with someone other than her husband gets the normal death penalty  [choking].\\That is just in the regular laws about עריות forbidden sexual relations in Leviticus.

But in Deuteronomy you get the law about מוציא שם רע which also refers to a married woman --but to a special case of a married woman-- the נערה בתולה מאורסה שזינתה a girl [12 years old to 12.5]

The case you might recall is where a husband makes a false accusation against his wife. He says (after the Chupa, and  they had sex) that he discovered that she was not a virgin. But then it turns out that he was lying. Then he has to pay about $1600 [100 shekels] and 39 lashes. 

But if it turns out to be true she is stoned. 

The case to Rambam is she had sex while betrothed  [ or even after the chupa but before sex with her husband] and thus when the sex with her husband took place, she was already not a virgin. So she is stoned. But here is where the opinion of Tosphot is the law about stoning is parallel to that of מוציא שם רע [slander] that is-- she is stoned only when the husband said to witnesses, ''Come and give testimony.''     

[I admit I am being short here. Sorry about that. Just for the sake of clarity let me add a few details. The case where the husband is found to have lied is when he did ask witnesses to come and they came and said they saw her have sex [on such and such a date and such and such a time] before she was married after being betrothed. They come and say that. Then two other people come along to the court and ask "How could you have seen that? Both of you were with us that that other place that whole day.'' So the husband has to pay the $1600 and gets lashes. But if no second set of witnesses come, then she is stoned. It is a case of a married woman having sex except the difference is that it was while she was betrothed. [Betrothal is marriage but before the chupa.]

[See Ketuboth page 45]