You need to pick your battles!  Is it really worth the frustration and aggravation?  Make a list of what is important to you.  If the two of you aren't together, then why not just file for the divorce.  Make it legal.  Your not doing any favors for your kids or yourself.  He is a grown boy.  He has made it this far.  His problem is he has always had you there to do it for him.  Once he realizes your gone, he will learn to sink or swim.  You need to learn how to release and let go.

My ex husband was the same way.  As long as I was there bringing in a income.  He was OK with working a mediocre job that hardly paid.  Once I left and divorced him.  He grew big boy pants and got a big boy job.  Now he pays me alimony!