Good job, keep detaching. I wouldn't mention the drugs to her, as I think it will get a bigger impact when she finds out rather than you telling her. That would be a 180 in itself if you didn't tell her about it.
Talking about your son is a great move. Keep it light hearted and enjoy the dinner.
The secret is to keep detaching. If you enjoyed your lunch with W's cousin, do it again sometime. Keep yourself busy and surround yourself with positive people. Keep going to the local watering hole and build a few friendships with the regulars.
Keep doing things with your son, and keep doing things for yourself. Trust me buddy, it will get easier with time. Don't worry about your actions or inactions, and don't worry that you may be pushing your wife towards OM or away from you. If you detach, GAL and give her space, this will work for you not against you.
You cannot change what may or may not happen by doing this. You can only change (for the worse) your sitch by still being there for her and trying to instigate things that she may not want at this time.
Slowly slowly, your sitch will turn a corner.
AndyV M38 W36 D7 M 13 years Together 17 years W wants D mid Dec 06 (ring off) W wants separation early Jan 07 (she backdated to Oct 06) EA revealed end March 07 (Nov 06 W first meeting with OM) Hallmark moment "I care for you but am no longer in love with you."