It doesnt look good really. This is going to be his career and 8 weeks in he's cheating.
I suspect now you know he probably won't do anything further, but it's a matter of trust eroded.
Every time you he goes away you'll be wondering if he's cheating. I'd feel really unsafe on the marriage and would possibly need to reassess the nature of it going forwards, if I was staying with him.
I'd be letting him know you're unsure if you can continue supporting his new career and that you feel the continuation of your marriage has seriously been put at risk because of his choice to get close to another woman.
By saying that...you aren't threatening to leave. You aren't giving an ultimatum...you're making him away of how you feel in light of his actions and he'll know that in your mind ending the marriage is not impossible.
You're in a strong position to make demands for how you want things to be going forwards. How long is he around for in January? Could you book some marriage counselling for then?
One of the things about this..mis the cheater doesn't really get how it is for you.
For him to get a little sense of your pain...send him this link
www.survivinginfidelity.com/forums.asp?fid=2
Just reading a few of those threads will give him an insight.