Originally Posted by
FutureTrip 
Also at the coparenting visit, he admitted that he doesn't count "slip ups" in his sobriety days. So when I ask how long he's been sober, to him the answer will always be August even if he has "slipped up" since then.
This says it all FT, as I'm sure any recovered A will confirm. If you're having slip-ups you're not sober. What you're doing is topping up and eventually it becomes more than that.
My suggestion is that you stick to they breathalyser agreement like glue. If he utters a peep, tell him you had understood he agreed to doing it before and after each visit, and if he would like to take that back you will have to rethink everything. Then never forget again until it becomes so routine that he never questions it again.