I understand your wanting to do this the right way, and I in NO way want to tell you how to do that. Might I suggest however that this be something the two of you do together. I completely understand that your wife is shy and timid, but this is a woman that apparently you both want to build a lasting relationship with. To that end, it will take the work of both of you and not just you. I have found that in order to make someone work within your already established relationship though that you might start as friends and see where that goes?
I wish you luck on your search!!! I hope you find what you both are looking for!!