...that as you work through this process you will be able to discern why it happened. I'm not talking about excuses, just reasons. If you're both willing and able to be honest about everything that may have contributed to this. If that happens, you might be able to come to some level of comfort with him being gone. Too, it's unlikely that the only reason (or even the largest reason) he cheated was that he was out of town and 'could'. And he doesn't need to be out of town to do it again if he wants to.

I'm really sorry this happened to you I admire that you are thinking this through and willing to talk about it and giving it a chance. I would caution you (and like others have said, I'm sure I'm not telling you anything you don't already know) against talking to too many people or the wrong people, and only you can decide that. But if the two of you make it through this you don't want to have poisoned the well with all of your family and friends, who, as nossy says, will all certainly have opinions and advice that might not be helpful depending on what you decide is best for your family (though certainly well-intentioned).