I also agree with Puppy. At the stage where there is infidelity involved I would definitely take the bust it up approach. After a certain point though the affair has no impact on events.
My W and I are physically separated; I got served D papers; we are fighting over custody. I have signs she has someone. So what. It has no impact on custody or a D in my state. It's her life, she can do what she wants. I don't care whether she has someone else or not at this point - it's irrelevant only because I have detached from her. Hope that makes some more sense.
MySitch Me-47 STBXW-41 D-5 S-8 ILYBNILWY-01/08 Want a D- 01/09 Physical Sep-01/10 D filed-06/10 Got 50% custody=09/11 Ride that wave!