Which term best describes the irrelevant argument presented by the husband about past vacations?

The term that best describes the irrelevant argument presented by the husband about past vacations is "inconsequent argument." This type of argument refers to a viewpoint or claim that does not logically relate to the matter at hand. In this case, the husband's mention of past vacations does not address the current issue or question being discussed but rather diverts attention away from it.

Inconsequent arguments often arise during discussions when one party introduces unrelated information in an attempt to validate their position or deflect criticism, which exactly fits the context of the husband's remarks. This is different from other types of arguments like red herrings, which intentionally mislead or distract from the main issue, or straw man arguments, which misrepresent an opponent’s position in order to refute it. Shifting the blame, on the other hand, involves placing responsibility for an issue onto another party rather than engaging with the original concern.

In this scenario, the husband's irrelevant reference to past vacations serves only to distract from the ongoing conversation rather than contributing any relevant or constructive insight.