Indeed, everything is fine in moderation. Though, you know, there are far worse things he could be doing, at least this guy isn't in a bar chatting some other woman up. She should be pleased that he's home at least.
On the other hand, perhaps she has identified that he's not making the most out of life, perhaps he should take up some other hobby for a bit that they can do together, or just sit in the living room and read a parenting book or talk about how her day was.
Personally, I've never had any long runs of gaming, they get boring, but I still find computing itself to be quite absorbing and perhaps the mrs doesn't like this. So, from own experience don't spend more money on gaming hardware.