Print this and show it to your wife. I am an architect with a lot of experience with wood, and humidity.
First thing is wood "breathes" and the moisture content will rise and fall with the environment. As the moisture content changes the wood shrinks or expands mostly perpendicular to the grain. This expansion can also cause the wood to check (as in timbers) when it gets particularly dry. It can take a while for this to happen, and the larger the piece of wood, the longer it takes. Wood and millwork items are often left exposed in a home for several weeks to acclimate before being installed.
The ideal would be for the moisture content of the environment to remain constant, which is quite impossible. And wood is best kept within a range of moisture content where it remains dimensionally stable, which is often quite impossible. So the next best thing is to mitigate the environmental changes to avoid the extremes. This is often done by heating and cooling our houses, however this has other implications.
Now, not knowing the climate where you live...
If you have dry winters and heat, which can dry the air further, adding moisture is a good thing. And it will take several days of weeks for the timbers to acclimate to the higher humidity. It would be better if you boiled a little bit everyday, but so long as your house is well sealed, the water vapor you are putting out by boiling is not a problem and may be beneficial.
In more humid environments, however, it would be better if you vented some of that moisture. A kitchen hood vent would be fine to remove most of it, and you can always open a window, or your air conditioning system is quite able to remove the excess moisture.
No matter which condition you live in, it still takes several days or weeks for the wood to fully acclimate, and the moisture you have produced will have dissipated before that ever happens. And then, the natural changes of the weather will have a far greater impact that your beer making.