I guess I'm not understanding how 'slow and steady' with H is realistically going to land us where I want to be?
It can be done, and although I'm clearly in the "come down hard and early" camp around here, there ARE advantages to the "slow and steady" approach (less damage to the wayward spouse that you'll have to salve for one). MOST of the reason I advise against going slow is YOUR ability to handle it. It takes a really incredible person to be able to stand for more than about six months, I've found.
However:
a) you ARE a pretty incredible person, mdu, when you keep your emotional reactivity in check -- I think you can do it!; and
b) as was just pointed out to you, your relationship with your H right now is pretty good -- not a lot of confrontation and adversarial stuff like a lot of us were going thru.
I recommend coming down HARD AND FAST when there is a definite PA or EA, the betrayed spouse knows, the wayward spouse KNOWS that you know, and then they are unrepentant/in-your-face about it. Because in those situations, a lot of damage can be done by the entitlement-fueled wayward spouse, and they will also rapidly lose respect (and therefore attraction, and therefore LOVE) when they perceive the betrayed spouse's "standing" as a sign of WEAKNESS.