Hey LG. I think it's good that he is willing to be accountable via the keystroke logger.... but I think his being aware of it rules it out as a way for you to really determine anything. If he knows there is a keystroke logger, he will not do anything he doesn't want you to see on those computers. If he DID NOT know about the logger, then you'd have a real snapshot of his behavior... but with him knowing, you have a snapshot of what he wants you to know.
Which really is just the tip of the iceburg. I don't know that there are enough keystroke loggers, survellance, snooping, checking, etc to truly know what another person does. In some cases, you just teach them to hide things more cleverly.... but I'm not sure you can ever monitor or control another person's behavior.
Personally, once my trust has been betrayed, I need to at least "spot check"... to either find misbehavior, or hopefully good behavior. But spot checking is random, and it can't be expected or predicted by the other party or it's useless.
I know I resorted to snooping and checking on my ex once I did not trust him. Now, I wonder why I bothered. Because what I found did not make a difference in what I did! If I found him "innocent" I was not reassured, my trust was not restored. When I found more bad things, it was not enough to make me leave. Looking back now, if I had known I could never trust him again, I should have given up. And I should not have snooped unless my findings would determine action... ie if I had known that one more occurance was the final straw that would break the camel's back, and that I would leave if I found one more occurance... well then it would have had a purpose. But I'd find more, and it would lead to a confrontation, and to him hiding his sins more cleverly in the future.
I don't know what to suggest, but I don't think there is any way for you to totally monitor his behavior. And I don't think you are at a place where you can say that if he contacts one more woman/has one more inappropriate contact/whatever that you are out of there. I just see it as keeping you like a hampster on a treadmill; but going nowhere. I fear you will exhaust yourself, and not feel any better.
From a pratical point of view though, why bother with a keystroke logger that he knows is there?