OK, that's tough. And what I've got to offer next may sound pretty calloused, but I think you'll see a ring of truth in it.
It doesn't really matter, aside from whether it's fraud or not, what that charge was for. I know how counterintuitive (and isn't that a $5 word?) all of this is. Everything your heart is SCREAMING you need to do is not what will help you. Think of it in terms of a bucket hanging from a rope. You're both in the bucket. He's leaning out. There's a possibility that he will tip that bucket all on his own. But, it becomes far more likely to dump if you do anything to reach for him and shift the balance the rest of the way.
Decide for yourself right now, would him seeing someone else be a deal-breaker? I'm betting it wouldn't. I've been there. In my case, there turned out to be a couple of affairs, with both sexes. (Gotta love drugs and mental illness.) Thing is, an affair, browsing a dating site, anything like that, regardless of how harmless or "degenerate" is not a reflection of you or even their feelings for you. It's a reflection of their problems, and their hope that they can find something, anything, to salve their emotional pain.
My personal suggestion is, accept those realities and act as if it's done and in the past. If it's something that never happens, then it's really easy to move beyond. If, and I hope it never does, but if it comes to pass, then you've already started to deal with it, and worked to understand the truth.
Even though you don't see it, your husband is hurting and confused in a way you and I won't really understand. He's looking for a band-aid to make it better NOW! Rob1231 on the "Piecing" forum has a great band-aid analogy. He relates it to affairs, but it really applies to all of the goofy things they do. A band-aid covers the wound temporarily. But, band-aids quickly become crusty, curl at the edges, and fall off. And unless something is done to treat and heal the actual injury, the band-aid has done nothing but cause more pain when it's pulled the rest of the way off.
I think turning off your berry and taking your own time was brilliant. (By the way, I am addicted to my Crackberry. My PIN is in my signature.) Do those things for you. You are not there for his convenience or beck and call, and that's something he needs to learn through example.