The Sorrowful Suitor

 refers to an unmarked quest in the Fallout 3 DLC Broken Steel.

Walkthrough
In the Presidential Metro, on the opposite side of the hall with the train to the Adams Air Force Base exit, you can find a holodisk called Sorry, My Darling. The disk contains the apology of an unnamed woman to her "darling" for not being able to make it to their meeting point in La Maison Beauregard after all he had to go through to get the "special gift" for her.

Arriving at La Maison Beauregard in Georgetown, you find that obviously her beloved is no longer among the living either; instead, you are greeted by a hostile character called Lag-Bolt. Aside from his unique armor and shades, he also carries the key to a suitcase nearby in which you find the special gift, the All-Nighter Nightwear.

Reward

 * All-Nighter Nightwear
 * Lag-Bolt's Combat Armor
 * Lag-Bolt's Shades