I've been thinking about roughly this question a lot the past few weeks. My best guess is the end of sexual fidelity and/or self modification to remove sexual jealousy. Were I to be frozen and then thawed, and find that poly was now the norm I would honestly be disgusted and afraid. The kind of love that I had hoped and dreamed of would be effectively dead. None the less, I know that even with our current mind design there are people today who are poly and seem very happy with it. It seems at least plausible that without the complication of jealousy, romantic love could be that much more Fun.

I don't want this to happen, not at all, but if forced to make a guess, that would be mine.