I guess I did the testing of this without really thinking about it. I had made two sims for each other, they romanced, woohooed and everything else that goes with the relationship and became engaged to the sim. He met someone else and they really hit it off, all he could do was think of the sim, so I did the enteraction, just be friends.......he moved out and proceeded to marry the other one without a problem. Another couple, I did the same thing with and used the interaction, breakup and could not get the enteraction for going steady or anything, not sure if there is a difference in using breaking up or just be friends. That is what happened with mine anyway, so I have tried a few others with "just be friends" after they were engaged and was still able to proceed with engagement of another sim. This was right after WA was installed and this was with the Heartbreaker LTW.