Here's your "female" perspective

Cheating does not automatically award custody to the "non-cheater" but it's a damn good place to start - and you'd probably get better than every other weekend visitation. Basically you would want to prove that her actions are the ones that ended the stable homelife for you and your son, causing you great grief. You gotta get a lawyer - I've got a great pro-dad lawyer if you want his name.

And about her being pregnant with a dude's baby that she ain't even with anymore - I don't know how long you guys have been seperated, but that seems a little quick to move from being together 8 years married 6 to already being pregnant. And honestly, I wonder what ol' 20 year old dude's gonna do with two kids by two other dudes in his little sportscar....

Sorry if I was less than helpful. It's apparent that someone wants to sew some wild oats....