I would suggest building on the alpha manliness by avoiding relationship talk altogether as suggested (^^^) and simply say that there is no point in discussing anything as long as she's involved with someone else, that you're not interested in an open marriage. And then just keep taking care of business with the home, kids, and yourself, and give it some time, see what happens.
I'm no expert but many good MC's won't work with a couple if the W is actively unfaithful.
