About Drake and Elena's Relationship?

Drake and Elena's relationship is a topic spread thinly across the game. There is the cryptic exchange between Drake and Sully about Elena "still wearing it" and the final scene where Drake recovers a wedding(?) ring.

This made me very confused throughout as I thought I had missed something from Uncharted 1 (which I have never played) or Uncharted 2 (which I might misremember).

From some research, I have confirmation that "it" is indeed a wedding ring and that somehow Drake and Elena drifted apart before U3. I also see people mention how they've indeed married or been engaged and that it's been two years.

My question is: What's the whole story on this topic and where is it explained (if anywhere)?

I'm assuming the whole thing might just be implied (after all I managed to guess as much myself), but I would like to be sure.

After a bit of research I found the following:

Nate and Elena marry in unknown circumstances. However, Nate's phobia of commitment and lust for adventure places great strain on the marriage, and the two separate, becoming estranged. Elena keeps her wedding ring, and Victor Sullivan looks after Nate's without his knowledge.

...

Between Uncharted 2 and Uncharted 3 Nate and Elena were seemingly married. This is indicated during the third game when Nate states that she is still wearing her ring and Elena answers that it helps in this kind of country (Yemen) to keep unwanted admirers away, though she is wearing it because she still loves him. Unfortunately at some point before the events of Uncharted 3 the relationship broke again, one of the reasons being the grenade injury she sustained, from Harry Flynn in Uncharted 2, which nearly killed her, the fact of Nathan Drake's dangerous and agitated life being a risk to her safety (his attempt to protect her because of his love for her) and the obsession with Drake's ring which becomes his life which she does not want to be a part of.

...

Chloe deduced that Elena broke Nate's heart. In Uncharted 3: Drake's Deception, it is implied that their romantic relationship was challenged by Nate's inability to settle down. When Nate tells Elena that she loves the dangerous world of treasure hunting as much as he does, she simply replies, "not anymore."

I hope that there is anything what you were asking about. I didn't find much more to tell you.

Sources:

• http://uncharted.wikia.com/wiki/Elena_Fisher
• http://uncharted.wikia.com/wiki/Nathan_Drake

No, you didn't miss much. They kiss in the end of Uncharted 2, that's it. If the "whole story" is told somewhere, it would be in some comic, or somewhere other than the first two games.

It makes the game seem more realistic. In real life, people don't stop and laboriously explain things everyone in the room knows. So the writers put enough in so that a sensible person can connect the dots.