[This message edited by knightsbff at 8:38 AM, June 11th (Tuesday)]
IMO, the best you can do is to do your best reconstructing your own memories in the light of your partner's memories.It goes both ways, since the different memories indicate uncertainty about what really happened.
Of course, if one or both parties is lying about their memories, all bets are off.
How we have chosen to handle this, is first, my husband dealt with his conflict avoidance. This caused him to agree to do things or make arrangements with me that he sorta never really had any intention of carring out. So, that fixed things mightily.
Additionally, we made an agreement that we both came to our conversations with good intent. Neither of us had any desire to harm the other, so we enter into disagreements with that belief, instead of another, such as "that asshole meant to do this!" This helps diffuse disagreements because they don't become power struggles, they become opportunties to figut out where the disconnect is and how to fix it.
In order to make your communications effective, it is likely you will both need to dig down and figure out the root causes. Miscommunication and disagreements happen - we are human. My husband and I can say or hear the exact same sentence and get totally different meanings. It doesn't mean one of us is right and the other is wrong. It means we are different, and treating one another with respect while we figure out where the wire got crossed is critical to finding an effective solution.