I agree with painter - actions speak louder than words. No need to give him any "heads up" about what you are going to do because that will just cause arguments before and after you do it. Also, snooping is hard to give up (I was still doing it after I found out about A, too), but it doesn't help you detach and, really, what is the point? You know he is a cheater and a liar already.
Would it help you to make a list of all of those things you listed and just leave it on table with homework and supplies when he has the kids? It may help you have less uncomfortable interactions that may lead to confrontations that you would like to avoid. When I was very angry at my H, the more I could write down and the more "routine" things were, the less we had to talk. That led to less fighting especially in front of the kids.
You seem to be doing better! I am so glad. I am thinking about getting a tattoo, also. Love the idea of the arrow, but I do not like pain so maybe not my foot :-)
M 44 H 46 M 20yrs T 25 yrs S15 S12
ILYBINILWY 7/18/15 Move to MBR 9/8/15 Physical Separation 10/10/15 Suspect A 8/2015 Confirm A 12/27/15 D filed by H 2/2/16