No, because you see he went back in time and then changed the future events for himself in a new dimension!
You see, there is still a dead Lois somewhere in another world, and since the Superman of that dimension left his time to go to another time when Lois didn't die, he created two Earths, one where Lois is dead, Superman is gone and Lex rules the world, and one where the opposite is true.
It's all relativity, Time is a continuous forward motion of events. For Superman it continued to move forward even though it appeared to move backward for everyone else to him. While to everyone else they were still moving forward in thier respective times, he just went to another dimension that had the same events in a different part of time for them.
Thus we see that Superman is really willing to sacrifice a whole world to torment and despair as long as he...
A: doesn't have to look at it
B: gets the girl
......Or I guess it could just have been a really bad idea. It could go either way.