Sounds like you are working on this from a position of strength. It's important, when the bottom falls out of your world, to get your feet back under you and work hard to protect the most valuable things in your life - your kids.
I have two boys of my own. Thankfully my ex-spouse was lucid enough during her life change to recognize that they belonged with a parent who was willing to be responsible. It was the best gift she ever gave me.
I personally don't buy the "MLC is a mental illness" deal. Yeah, depression is usually in there, maybe some bi-polar like symptoms, but in general we see people making life altering decisions, hurting people in the process, and they are quite well aware of what they are doing.
Temporary insanity? Hmm. Maybe. Sounds good. Except in most cases the "temporary" has a time frame of several years.
They become mean sometimes, hateful even. They become the antithesis of who and what they were before. Yet, while all these things are irrational looking to us, they make these decisions consciously and will defend them loudly.
In the end, don't think it really matters which way you lean in this great debate.
Bad actions are bad actions. Regardless of the cause. Surely no one really believes that "the devil made them do it."
Jack is right that it's a call that we each get to make on our own. Listen to all the differing voices if you so desire, but in the end you make the decision that YOU can live with.
The best thing you can do right now is to continue showing your sons how a real man handles the crappiest moment of his life.
Blessings,
Bill
"Don't tell me the sky is the limit when there are footprints on the moon."