You should speak with an attorney about how leaving may be viewed in court as abandoning her and your children. Be aware of the risks involved in leaving.
You are supporting her actions by not taking a stand. Some have cut off the WAS phone because they weren't going to spend a penny of family money to support an A. And other similar type actions. Alarms on the doors that go off when she comes home late, etc. But without any actions demonstrating you are serious about not having an open marriage nothing will change. She will have her boy toy, her family, and all the benefits and none of the consequences. Maybe she tires of this OM, there's nothing to stop her from another.
Me:49 W:45 M:19 T:22 EA confirmed and ended 8/2014 S:19,17 D:9,5