Quoted from NickBuffaloPinball:

Pinball takes away both time and money that could be spent on significant other or children. So, this could trigger some pyshcological/biological maternal instinct that says time and resources should be spent on her or offspring.
My guess is this is only a major issue if there are extremes going on, i.e., extreme spending on hobby at the cost of time spent on her or children. Or, if she is extremely needy and mentally unhealthy. Or if there are underlying relationship problems, this could be an easy target.
This is brought you by Gusphan, amateur and unqualified psychologist.