Move on with your life..your own life..
If you wife comes back, consider it a bonus..Give her a
chance..but make sure you don't give in to her so easily..have her
earn it back.
However you should nonetheless hire a PI to get proof of her
affair..so in case in future she decides to have another affair
(touchwood) you can proof of her past offence..so she can't have
the rights to touch your money.
"Man can forget but cannnot forgive, Woman can forgive but
cannot forget"
Just to prepare yourself for the worst case scenerio..its better
to be prepared than to be caught unprepared.
Try to be of close friends with her sister friends as well, so
at least they can flag certain tell-tale signs to you if it is
still happening or another new affair pops up in future.