To me (and please remember that this is my opinion), this is two separate issues: marriage and career.
I understand that they may appear to coincide when it comes to one's life and livelihood. But if there is a problem in one, that must be resolved. The best way to resolve a problem is to figure out the issue then making strides to correct them.
In this case, the bigger problem appears to be infidelity in the marriage. This is what needs to be focused upon. If this problem is 'resolved', the career should not be a large concern.
So I would say try to figure out an understand why a husband would commit adultery. This will lead to healing the wounds and prepare you on a path to slow recovery.