Ulysses and you have some dark history which you seemed to have forgot.
Obviously Ulysses wants’ you to repay your debt to him or someone you both knew of which he need's two people to detonate the nuclear bomb as shown in the picture of him and he decides for you (alone meaning lonesome) to help get all the 'normal wastelanders' out of the divide before you detonate the bomb in the divide to kill all the evil and mutated creatures and people left. When you return to Ulysses to detonate the bomb you can have a change of heart, this can trigger a fight between you and him.

OR MAYBE

Ulysses and you have some dark history which you seemed to have forgot.
Obviously Ulysses wants’ you to repay your debt to him or someone you both knew. This debt you owe can mean Ulysses want's you and him to have a fresh start and needs you both to put your past behind you, a clean slate so to speak? And what happens when you use a nucular bomb? It creates a new slate, a new world and a new life.

i dont buy the "seemed to have forgot" part.......


you remember your past according to some of the dialogue.... you have stated you have been to new reno and the divide.....

i doubt you would remember that, yet forget that you had interaction with someone like ulysses......

if you read the part about your relationship to ulysses form the vault one of the developers mkaes a statement:

Ulysses' dual obsessions with the Courier and the Divide seems to suggest that Ulysses may in fact be one of the fabled survivors of whatever happened there, and that Ulysses' seeks the Courier for their involvement in that event - whether it was conscious or not. The possibility that the Courier may not even be aware of his or her own involvement in the event is also something hinted at by Chris Avellone, who stated cryptically, "I also have a lot of love for Ulysses in Fallout, only because I like the idea of someone hunting my player for reasons of his own, and then hearing the reasons why… and realizing how important even the smallest of my actions are for the people of the wasteland – living or dead".[12]


so it seems that there was something you did that affected ulysess and the divide and it was such a small action of yours yet had a huge impact on them both......


so while i agree that there is some sort of dark history between the two, it doesnt seem that you and ulysess have ever met face to face before......


and of course, by "you" i mean the fall out courier and not you the poster specifically.....

I love the mystery and instagerity behind the courier and ulysess's relationship and its been a story ive been itching to find out every since i realised that the name and refferences where folowing me through the game, i think it will be a sad end to a long living story and that it will shock the audience in the long run.