I wonder why his wife had to be at Github at all. I've worked at half a dozen startups now. Never would a spouse of either gender be in the office, and if they happened to maybe communicate with anyone, it was only a quick introduction and then they got out of your way.
I've been in a couple Midwestern start-ups, and founder's spouses (wives, in both cases) often did come into the office. Generally they were going somewhere together, or whatever. Chatted several times, and it was no big thing.
When they did ask how things were going business-wise, I got the nod from their husband. Turns out, they were also on the hook (co-signatories) for much of the start-up capital vehicles/loans/lines of credit.
Their money on the line, they own the company, IMHO.
I would consider it highly inappropriate.