DA,

There does come a time when you can only take so much. In my case I have been validating my WIFE's feelings now for almost eight weeks and so far it has not worked one bit. So far she gave me some of my Xmas presents back, threw aways cards and flowers, and accused me of having an affair which is completely untrue.
In my opinion, talking to the MIL is not a bad idea. There are two sides to every story and if you are honest with yourself and everyone else then talking about it is not bad. I have done soul searching and do advise you to do the same but. In my case I only converse with 3 people about this so at least I have someone to discuss my issues. My wife on the other hand now talks to everyone else about our issues but her Mom and has not once validated my feelings during this time. Again, seek professional counseling like I did and that way you have an avenue to discuss stuff with someone other than your MIL without worrying about it getting back to your W.