A more thorough explanation:

Poenae secundarum nuptiarum is a Latin term that means "penalties of second marriages." In Roman law, these were the disabilities imposed on a parent who remarried to protect the interests of children from their first marriage.

One of the most important rules of poenae secundarum nuptiarum was that all the property acquired gratuitously by the parent who remarried from their deceased spouse, such as gifts, dowries, or inheritances, would become the property of the children from the first marriage at the moment of the second marriage. The parent who remarried would only have a usufruct, which means they could use the property but not sell or dispose of it.

For example, if a man remarried after his first wife died, and he had received a gift of land from her family, that land would become the property of his children from the first marriage when he remarried. He could still use the land, but he could not sell it or give it away.

The examples illustrate how poenae secundarum nuptiarum worked in Roman law. The rule that property acquired gratuitously from a deceased spouse would become the property of the children from the first marriage protected their interests and prevented the parent who remarried from disinheriting them. This rule was one of the many legal protections for children from first marriages in Roman law.