If you tell him......?
We have a practice called Play the Tape Forward.
If you told him you were getting support from an internet support site, his reactions may be _____________________.
Some common reactions: angry, threatened, blame-shift the problem to you, and use this as another reason to get drunk.
Some magical thinking ideas of what might happen: he will suddenly reazile he has a problem, he will suddenly begin to see how his drinking is uppsetting you, he will beg your forgiveness, he will magically become the man you want him to be.
Because the common reactions are the experience most of us have when our Alcoholics find out we are getting support for ourselves, I recommend you lock your computer with a password and always log off when you walk away from the computer.
Alcoholics don't respond well to finding out that their status quo of *whatever I feel like doing, whenever I want, and your feelings don't matter* begins to change.
The 3 C's:
You did not CAUSE this
You can not CONTROL this
You will not CURE this.
Alanon, SR reading/posting, and self-improvement books are actions you take to help yourself. You are worth the effort!