Rob,
Maybe you need to help your wife. By that I mean, don't just go to her and say "I want spice in our sex life and here's what I want YOU to do" but approach it in a way that she won't feel that you're attacking her. She may have been raised conservative when it comes to sex and feels that if she does anything out of the ordinary, then it's wrong. You mentioned that she's not good at initiating or touching. Well, that should give you a heads up that you need to work with her on that. I know that we're open to do almost anything with our spouse sexually, but a lot of us do have hang-ups and I know it's frustrating.
Just keep in mind that she is a woman, she will be sensitive about this, and it may take a few times (or more) of talking to her to get her to open up to the idea. But BE PATIENT! All of this coming from a woman's perspective :)
As for you thinking about divorce over this, I understand that this is a big frustration for you, but I don't see this as a means for divorce. There has been no infidelity, and I don't remember the bible mentioning "not having a good sex life" as a means for divorce. I'm NOT putting you down! I understand this is a very important part of a marriage! But, don't let this end a marriage of 22 years!!
Just help her. Approach it as something that both of you can do together. Say something like "I really want to share new experiences with you. I think it would be fun if we..." That way, she's not seeing it as her fault. And start out slow...don't try anything and everything on one night! It sounds like she'll have to really warm up to the idea of all of this (although it's not out of the ordinary) so remember to not be pushy. Even if you have to initiate it more and actually tell her what to do...she may not have a clue or may feel uncomfortable doing it and that may be holding her back as well.
There is a book that may help as well. It's called "Becoming One: Emotionally, Spiritually & Sexually." In it "you'll learn step-by-step how to nurture intimacy with your spouse at all levels of your being." You can go to
http://www.joebeam.com/becexp.htm to preview and order it!
It has won awards and is a best selling book in the Christian market. I really believe this will help! And it will show your wife that there are a lot of things she CAN explore with you and it's perfectly ok :)
All this is just my opinion! So, you can definitely take it or leave it! But, I do hope things get better and you really think about what divorce would do to the both of you...and your kids if you have any. That's just not the way to go! Look at all you have invested in these past 22 years. Divorcing over a bad sex life is so ridiculous! Especially when it CAN be fixed. You just have to approach it the right way.