Dear Mr. Postman (слэш)

“I’m um—your mailman,” Bucky says, lamely. He mentally kicks himself. He’d—sort of—practiced this! I’m your old pal Bucky, good to see you again!
The corner of Steve’s mouth quirks up as he glances down at the envelope on top, absently, then back up at Bucky, eyes crinkling.
“I had a suspicion that might be the case, Bucky Barnes.”
Bucky lets out a surprised breath in a rush. “Oh! You—you remember me?”
Steve’s half-smile turns into a real one and he tilts his head at Bucky. “Of course I remember you Buck. Wasn’t sure you recognized me though—it’s been a long time.”
***
Or—Steve and Bucky revive an old friendship, get married (but totally just as friends, for reasons), and navigate a few of the many trials of the heart that come with falling in love with your best friend.