I'm not sure if I can give better advice that LauraOh's.
But I do recall being at work for the first time after I discovered my wife's affair and being just filled with rage with no way to vent it. And I really feel for you.
You definately have to focus on you, but the kinds of emotions we feel in these situations are very powerful, and I think venting is important, just don't let it consume you. One of the best things I learned from the various materials and support I got innitially was that we have more control over our emotions than we think. So you can choose to feel that anger and then focus on something positive like a goal.
Reward yourself. Plan something little enjoyable thing you're going to do every day. That way you can face the fact that your situation is awful, but you at least you have X to look forward to in X number of hours.
Age: 28 Wife's Age: 28 Relationship: 10 Years (dated on and off) Married: Less than one year Seperated: 1.75 years, finally served with D 4/30/2011