My wife actually played in my Shadowrun game for over a year. She had a rigger, and is quite a technology enthusiast. She had a lot of fun with it. Of course, she realized that she was getting no favorable treatment as well. She's also played in my DnD game, and is showing quite a bit of interest in my Arcana Evolved game that I'm building and is going to help co-GM it.

I seem to remember a time when it was the "nerdy" thing to do to roleplay. So we never invited anyone else to it because when we described it, a lot of people were turned off from it.
It wasn't until a couple years ago that we found out a lot of people were wanting to join in, but were worried by our clique-ish behavior. We'd have KILLED for more players!

I think it's a very treacherous road for a signifcant other to play in. It definitely takes mature adults to do so. One of my friends had his wife play with us, and a year later, they're divorced. It didn't help there were underlying issues between them (and she cheated on him with one of the other players) but it still kind of soured my take on it. Then my wife wanted to join, and I was admittedly skeptical. But she's proven very mature about it, and when something bad happens to her character she tries to figure out a way out of the situation and not yell at me or withhold "services" if you understand my meaning. If something bad that took some planning happens, she'll even compliment me saying "Wow. That was clever of them" or something to that effect.

My advice on seeing of a significant other is appropriate for your game would be to do a one shot game. Use pregenerated characters and a pre-made module. That way, if things don't work out for her she doesn't feel obligated to stay and no damage done to an established campaign. And if it works out, try a couple more down the line and eventually propose to joining in the long-term.

anyways, that's my two cents on it. Hopefully this helps someone.