The marriage/sex counseling stuff seems like something you'd want to give a whirl if it hasn't already been whirled.
I'd bet her perspective on the matter is a lot more complicated than "I'm just not in the mood." Especially if she's saying you can go fuck someone else and she's fine with that. Seems a bit like a cry for help. On more than one occasion womenfolk have been known to be more complicated than 'wants to fuck me' vs. 'doesn't want to fuck me.'
I'd bet her perspective on the matter is a lot more complicated than "I'm just not in the mood." Especially if she's saying you can go fuck someone else and she's fine with that. Seems a bit like a cry for help. On more than one occasion womenfolk have been known to be more complicated than 'wants to fuck me' vs. 'doesn't want to fuck me.'