Missmac, this is the way I see it.
If someone had a mental illness, say depression and they needed to go to a facility for treatment, you might be there for them. So how is this different.
Generally, if you have a relationship with a person with mental illness, A. They get help and B. They are not hurting you every 5 minutes.
Therein lies the difference (and where the unwarranted guilt comes from).
You want to stay out of contact, you want to focus on your healing and your peace of mind and take care of your Son. You know that if you get involved in all this, that won't be the case.
My point being, alcoholism is a "thing" that lashes out at you, that drags you in and tries to destroy you (just like it does the alcoholic). Sorry if that sounds over-dramatic, but it's how I see it.
It's also a proven fact that everyone involved with an alcoholic is affected by it.
Yes, he is trying to seek recovery, but he has been at it all of 10 minutes so the chances of you being hurt here are great. Yes he needs support but as Hawkeye said, he has a ton of support.
You need your own support network, SR, your friends and how about therapy or Al-Anon/Nar-Anon, are there any in your area? Even a single Mothers group.
I think you are making the wise decision. You do absolutely need to protect yourself.