I don't believe that "Oswald's feelings died when Ed shot him" or whatever. I have an immense trust in Robin's acting, I know he'll deliver the exact expressions that show us Oswald's feelings. Oswald's hurt, ofc he'll seek revenge because his character doesn't revolve only on his romantic feelings. However, it's clear (as noted in the reunion scene, oh tension) that he's still pretty much full of feelings for Ed (old & new & contradictory). His feelings grew much & can't vanish just like that.