I agree with Hamster, by and large, though I can completely understand if financial distress motivated her decision. Additionally, based on your post, you really didn't have much input in the matter...something I will address momentarily.

Largely, to me it seem like the underlying issue is a severe lack of communication between you two, stemming from a seeming unwillingness of your wife to communicate. While I don't think it necessary that a spouse report and ask permission of necessarily everything (it's a partnership, not a hierarchy), the...intimate nature, I suppose, of what she's doing I think should've at least warranted a passing question on your end BEFORE she posted. Additionally, her communique with the guy in question was entirely out of line...the nature of what they were discussing was, in my opinion, on a sexual and personal basis (despite declining physical contact, she was willing to indulge in part his fantasy, which, following an admittedly pessimistic line of thought, are the first steps to a bad road), and the fact that she agreed initially to sell to the guy can be argued as such as well. She knew full and well what purpose the milk served to him. Again, while I can perhaps understand finances are tight, that should've been discussed in full with you.

I am glad to hear that she has ceased contact with the guy. That is a vital first step in working things out. But she MUST be willing to talk to you about things...it has to happen. The three big pillars in any relationship are honesty, communication, and respect. She has, in part, violated all three. Were I you, I would sit her down and try to have a talk with her. She needs to understand that you, as a couple, need to communicate, and you need to make her understand the severity of your perception (which I do think is correct) that she doesn't value your feelings. She should also take some consideration into your proposal for marriage counseling. Ultimately, she needs to be cognizant of the fact that she is your partner and your wife, and thus she needs to, to keep with the analogy, include you into the team. Otherwise...I'm not sure this can keep up.

Please know you are in my prayers, and I hope things work out for the best.

Hugs,
Harley

Edit: LDS stands for Latter Day Saints, or more formally the Church of Latter Day Saints, commonly known as Mormons.