The short answer to your questions is that we will never know the actual figures in 1950 America but somewhere between "more common than people thought" but "less than a full on pandemic" so as still to remain humorous to the average middle class family while retaining some sense of reality, because many people at the time were aware that either them or the neighbors have violence in the home.

The reason for this appears to be two fold. Firstly, the definition of "domestic violence" was (and still is) notoriously difficult to define and is still something that is being refined and revisited the more information we gather on this topic. As a result of this police records at the time were often incredibly vague, perhaps no report, perhaps it would only be called "aggravated assault" . (Beattie, 1960). Secondly, family problems are hypothesized to have an incredibly strong incidence of "under reporting" either because the victim may be afraid of retribution, the sense that "what happens in the family stays in the family loyalty" or because the victim may not even consider what happened to them as worth mentioning. For instance, if your significant other ever mildly hit you on the shoulder because you made a leud comment in public, does that count as domestic abuse?.

However with that being said one study I might direct you to asside from the 1975 National Family Violence Survey is Gelles' 1972 booklet "The Violent Home: A study of physical aggression between husbands and wives". (Gelles 1972). It's actually hard to find online so I would recommend just going to your library and finding it on the shelf.

The book deals with a lot of good stuff like what constitutes violence, the reason for violence, the types of violence, and the rationale of the people involved for why they did what they did or why they were the recipient of violent acts. In this study they took a look at families that were reported to have potential domestic violence incidences through the social service agency as well as families that actually have police record. They then went to the neighbors of those people who have no record of violence. It should be mentioned that this was in the early 1970s but many of the couples interviewed were as old as 40 or 50, thus they would have been newly weds in the 1950s.

Preliminarily they describe at least half of all these families as having some reported incidence of violence (either husband to wife or wife to husband) with the caveat that this could mean anything (throwing things, breaking walls, shoving, slapping, punching, threatening violence etc). However, less than 10% of neighbors report having "routine violence (weekly to daily)" in the home and 60% or more had no reported violence at all. 20% of the husbands interviewed admitted to hitting their wives at least once however, the researchers note extensively that many of these incidences of violence are due to both people "feeding" off each other during domestic quarrels and much less so than the idea we sometimes have about a drunken husband coming home to a frightened wife and kid (although this definitely was at thing during the time absolutely). Again this is due to the very messy nature of this type of situation where seemingly ever single incidence has some unique context to it. It should also be said that many of these statistics should come with obvious caveats such as under-reporting and the sample size of 40 neighbor families.

All that being said the main character of the Honeymooners was a lower middle class slice of life setting. For a man with no history of no physically violent behavior, the threat of violence was vastly more common than actually erupting into a rage one day and hitting your wife (at least according to some of the data in the book) which may contribute to at least some of the humorousness of the character in the 1950s.