Just a Husband:
You're back for round 2, and from what I can tell, you haven't bothered to get a professional marriage counselor involved. As bad as dealing with an affair is---recovery is often harder. Without a plan and professional help, people often fail.
It's time for you to get a pro. I'd suggest either the Harley's by phone counseling (888-639-1639 for appointments), or Penny Tupy (a MB trained coach specializing in infidelity) at
SYMC. This is the most important thing you can do for your marriage right now, and I would suggest that you do it before you make any moves to Plan B.
From the scenario you paint, it will be very difficult for you to force your wife to leave. Petitioning the court will likely get you out of the house. The suggestion of throwing her stuff on the lawn and changing the locks might land you in jail in some municipalities. You need the advice of a good family lawyer to explore your options. Several years ago, I was in a similar position---and I left my house and left the wife and kids behind (and the house paid for---I was the sole bread-winner). Although less than ideal, it was still a very effective plan B. The kids blamed my wife for me leaving (although they knew nothing about the affair). If your wife is not used to taking care of the house by herself---she'll find that an added source of pressure.
Plan A has an element that you may be missing: exposure of the affair. You need to collect as much evidence as you can, and then it should be presented to her family, the OM's family, and her friends and coworkers. If you work with one of the counselors above, they'll help you formulate a plan that will put these pieces in place, effectively.