Warning: frame challenge ahead!
Movie Amnesia isn't real
There is no actual medical condition where people lose their self-identity, but are otherwise healthy and without neurological damage.
Actual amnesia is sadly, just brain damage. People remember who they are, but they can't process new memories. There is no cure (definitely not a 2nd conk on the noggin), and it's permanent.
- Disclaimer: none of this is medical advice, I'm not a doctor, and
pretend I have written "usually" and "most often" in all of these
Interesting uses of "realistic" amnesia are the film Memento (2000), and an episode of Star Trek:TNG. Both use the main character's ongoing memory loss as a plot device that resets the character to square one.
Movie Amnesia is better than real
Unlike real amnesia Movie amnesia is understood by just about everybody. Since it was invented by writers it works exactly like deus ex machina.
That means it works as needed for the plot or emotional payoff. The amnesiac only loses what you want them to lose – like the specific memory that:
she isn't actually married to this guy, or that she was a Manchurian Candidate assassin, or she's just a housewife from NJ and not Madonna.
Probably the best "feature" of movie amnesia is that the character is a blank slate with a mystery past. TVtropes has a remarkable number of amnesia variations listed under Memory Tropes. (This one really is a time suck, you have been warned). Movie amnesia justifies major plot holes and keeps unlikely characters together. It's used so often, and so outlandishly, it might be anti-climatic to use it "just" for emotional feels (outside of a soap opera where an old relationship got written into a corner and needs a deus ex machina reset).
What is the character dynamic?
You've given us no perspective on these people, their stakes, their chemistry, their interrupted lives, or how everything has changed. What is important? What is their dynamic? These are the things that will make the scene work.
Consider the perspective of the amnesiac – are they skeptical, suspicious, confused? Hopefully they are not a doe-eyed sponge absorbing an infodump telling them "This is who you are." That's a scenario for gaslighting and psychological thrillers.
The mate is trying to pull memories out, not put them in. Depending on how long they've been together, and the amnesiac's close call, they may be doting, anxious, even impatient/angry. This character may be the more pro-active in the scene, but they don't have the power to actually solve the problem so this might be a real test of their character to adjust to the new situation (real life relationships rarely survive a radical change in dynamics).
One character has just experienced a loss and is at the end of their relationship, the other has just been born (renewed?) and is at the beginning of a new friendship. This is a character-rich situation with tons of dramatic potential.
If for some reason the scene is really just about one person retelling a bunch of events that happened in the past, all this dramatic potential is wasted. The amnesiac might as well be in a coma (or in the grave) if they are not an active participant with their own stakes.
Figure out the current dynamic between them and tell that story, the infodump is just what's on the surface. We should be seeing awkwardness and desperation and hope – but also we should be seeing a couple who "meets cute on a date" so we have a reason to care what happens to them, and see there is still a spark there.