You need to set some boundaries for what you'll accept in your marriage. For example, a good one is:
"I will not live in an open marriage"
Enforce this with totally open transparency; email accounts, facebook accounts, access to his cell call history, everything. He also needs to send an No Contact letter/email to the OW.
You need to protect yourself and your son from this affair ASAP. Also, the "traumatizes" by water stuff is just a load of hooey. It's not like you went all Lorena Bobbitt on him.
Have you read the Divorce Remedy? Grab a copy when you can from a bookstore or library. It'll help you get through the coming fun times.
Also, take care of yourself as best you can; eat healthy, exercise to relieve stress and become healthier, and grab as much sleep as you can.
Oh, and yeah, why would he want to end the marriage? He's been able to have consecutive affairs with no real consequences other than a shower in bed.
