Since Im polyamorous, thats not an issue for me or my partners, every one of us have done that at some point. Though for monoamorous people that is probably kind of insulting and problematic.
Yes even with exactly those words, which is a little funny :D
It is!
Turns out that living without the fear of your own desires and emotions is pure freedom. If you are in monoamorus relationship and fall in love with a third person, thats a threat. For me right now the same situation is pure bliss. I get to love another human after all, that feels great!