Ketubot 58 - What does the bride eat?
A Jewish girl who is married to a Kohen has the right to eat the Priest's portion of grain (terumah), which is otherwise forbidden to all non-Kohanim. What is her status while she is engaged? - Since the Kohen has acquired her as a bride, most likely by giving her a ring , she is considered "acquired by money" and is in the category of people who can eat the priestly portion.
However, since she may inadvertently give her cup of wine (for example) to her brothers and sisters - and they should not be allowed to drink it - the Sages decided that the bride does not eat the priestly portion (terumah). Others say that the reason is different: should the husband find some hidden defect, the marriage could be considered a "mistaken buy" and be annulled - and it will turn out that she ate terumah for no reason. Why is the reason important, if anyway she should not eat terumah? - In the case were she has a special eating place, the first reason does not apply, but the second still does.
Normally, the husband supports his wife, and in return she gives him over her earnings. However, this is one of the decrees established for her benefit, and she can opt-out of it. She can say, "I don't want your support, and will keep my earnings." The Talmud then discusses the status of her earnings should the husband decide to consecrate them to the Temple.
Art: Wine glasses by John Singer Sargent