well, I have never been in love with two people at the same time, but I know someone who has. I guess I didn't completely realize that he loved them both until one of them wanted very strongly for him to be mono with her. He wouldn't do that, and they eventually broke up. The heart break I saw when that happened was very real.
if you ask a parent which one of their children they love, their response is angry with the "i love both of my children eqaully." so why is it people can't seem to even imagine the possibillity we can love more than one person?