If he ended the affair (or already had), would you want him back, or would you want to consider wanting him back?
I'm not sure what you should do, but answering that question might help you decide how to respond when you meet.
As far as the drug testing...maybe worry about that IF he comes back. If not, until you are at a child custody discussion, it is probably a mute point.
BTW, if he's been seeing his boys a few times a week, he must love them. If you accidentally threaten that relationship with talk of sole custody and drug testing, I'd guess that he'd start putting up some serious walls. Do you want to have your sons lose their father? Keep this an issue about you and him, not your family and him.
Have you read "Mars on Ice, Venus on Fire?"...it is interesting and might relate a bit.
