When you learn your spouse has committed adultery, very often s/he will ask for another chance.
The wisest move is to grant that chance with some caveats, while you logically consider your options.
To rush to a lawyer, to deplete your financial and emotional wealth without long consideration is destructive.
Destructive to you, not to the adulterer who, if tossed out, has a place, has someone to go to.
And you have nothing and no one.
If you had somehow, mentally prepared yourself for the stray possibility that this would happen, what would you have done?