Is it possible to have eternal suffering/happiness without the other?

In heaven, one assumes that we will have "eternal happiness, joy, peace, etc.." and in hell the exact opposite: "eternal suffering, pain, anguish, etc". My question is that is having eternal happiness/suffering even possible with the absence of the other? Don't you need sadness to have happiness and vice-versa? (same goes with tall-short, pain-pleasure, etc..)