Honestly, I tell him. I tried my best to be as compassionate as possible each time something would come up, but I always told him.
2 examples. 1 day we were sitting down watching TV and he was flipping through the guide to pick a show. Oceans 13 was on, he said "you wanna watch that?" I said no. He says "do you mind if I watch it anyway" and I said "I would prefer not to. You were emailing your ex while we were sitting on the couch together, watching this movie, just x months ago, so I've already seen it and it just holds bad memories for me now". He was disappointed with himself, and apologized, and we picked a movie that we could enjoy together.
Other story. He was asking about taking the kids to the park one day, I told him I would rather go with him. He again asked why, he thought it would be nice to give me some time alone. I reminded him how he had taken the kids to park along with his laptop to "give me time alone", and he proceeded to not engage with them at all because he was cruising profiles. He had forgotten all about that. He broke down, cried so hard at how callous he was to his own children. It ended up being a very concrete moment for him to realize that his A DID affect more people than just him and I, and that the shockwaves would be felt a lot longer and farther than he figured.
So I think it's important that a WS is told of these things to help them realize the depth of their betrayal, and just how deep in the fog that they were. Plus, why should the BS take any blame for them not minding what we did while they were too deep in their A to protest or care?