This is the best advice so far, as to the naysayers about how she will slow up the group or get stuck to much, they must not remember their first days in the mountains.
The answer to your question is yes, I would, and have. It's a great experience. That said, not all groups want to take a newbie, this is something that would have to be addressed before the trip with all parties involved, and the terrain should be fairly mild the 1st time out to help boost confidence. Patience will be required, both from your significant other, and yourself, as you WILL get stuck - that's part of learning. Hiring a guide is a good idea, and some training on avy equipment is a must BEFORE you go. Whether or not you need AST training for your 1st ride largely depends on how experienced your group is, and whether they want to push into "iffy" terrain - a responsible group will not push you out of your comfort zone, nor will they lead you into high-risk areas. I've been mountain riding almost 25 years, and my best trips are with my wife. She puts on her "big girl" pants when we go, and the 1st ride of the season in bottomless powder gets stuck frequently, helps dig out her sled without complaining, and takes an express interest in keeping her machine maintained, too. (BTW, she rides a newer ProRMK that is set up for her). So my advice is this: Don't play the "princess" role, have a positive attitude, and be willing to learn. Ensure your significant other is willing to be patient, understanding, and to run at a slower pace (if going with a group, make sure they are all in agreement to guide and look out for the "newbie".) We were all new riders once, and there is NO reason that both sexes cannot enjoy this sport.
