Don't be afraid to explore the past if the goal is to get to the root of the issues. Remember that such instances are not the cause of the problem, they are merely the symptoms. If you do go down that road, it might reveal some areas that both on you can work on independently but more importantly, as a team.
Just avoid getting into situations where blame is assigned for things that happened. You mentioned that you avoided the "yes-it-did-no-it-didn't" type of discussion and that is important. What one person sees and hears can be very different than what another sees and hears. Isn't that the root of all conflicts?
Let the past belong in the past. However, don't be afraid to look back so you can move forward more secure.
I guess the best analogy would be the guy on a bike who gets cut off by a car. He rolls off the road into a ditch and knocks his head against a rock. Since he isn't wearing a helmet, he gets a gash with 10 nice stiches that will forever be a reminder. The next time he gets on a bike, he'll think back to what happened, not to blame the driver of the car (even though he was clearly the one who caused the accident) but rather to take the steps so that if a situation like that should occur again, he'll be better prepared. Obviously, he gets a helmet.
Look back not to see who was right and wrong but rather to see how you could have done differently, even if it means having to back down when you're right. Remember the basci rule of unconditional love: It is better to be happy, than to be right.
As for the piece of paper, don't frame it. It will just be a reminder of the hard times and the near-collapse. Get your H, have a nice candlelight dinner with some wine and a special dish, and burn the damn thing as the "special occasion". Put the whole episode in the past for good and look to brighter days.
