Ok....me jumping in again....I tend to this a lot lately...
One thing I can say is you don't need to file for divorce to establish child support...I notice that you are in California...me too...you can go to you local court house, Family Court Facilitator.....and file for a legal seperation....this is wise financially because should your H go off of the deep end financially like mine did you will be legally seperated from that too!!!....if you can't afford it they have a financial waver that you can fill out and the fee is waved...if you should decide later to file for divorce you can change your legal seperation to a divorce...I did it all myself...
They will guide you through the paperwork...you can find out how much CS he should be paying....CS has nothing to do with your earnings...it is based on his earnings...because it is assumed that you want to maintain the style of living for your child so you both contribute to that based upon your abilities....
If he gets upset I think the MC can deal with that...it isn't like YOU are taking the money to make him miserable...it is the money he OWES his child...period...
I would be very careful about leaving him unsupervised with his father at this point too...it seems that his lifestyle could present risks to your son...emotionally and physically....
Don't feel bad about snooping on the computer...sometimes our subconscience tells we need the truth...and we are ready to find it....it might seem like more then we can handle but it isn't...you will be fine...
Before you even consider anyone else in your life....if it does indeed come to that...you really need time to recover for yourself....people tend to run from one relationship to another without the proper grieving...they cut it off and start a new relationship...often time to bring with them the same baggage that they had in the last relationship...
So get a legal seperation....take time for you....get your finances in order....and focus on you and your son being happy...
And yes...it is possible that your H could come out of this...(how old is he?)....mine went off the deep end and did all sorts of foolish things...immature things...totally opposite of what he had always been....now he is coming back...it is slow but it is happening...
I was patient on and off....but I did hold myself together for going on 2 yrs. now....and I also have a son who was barely 9 when his dad walked out...he is now almost 11...I have focused on his well being....when his dad was MIA I had good family friends...males...that took him to movies, out to eat, to ball games, to play catch, to come over and play games with them....he did okay without his dad around...I restricted his dad's visits because he was too unpredictable for me to trust him....I asked for and received full legal and physical custody with child support plus medical and child care in that...but then he didn't work and lived on credit cards so that left me with squat....but if he were to ever take off again....I can ask for all that back CS....he wouldn't be able to support an OW, lol...