Miis fall out of love?

Based on the previous games, can Miis fall out of love if you wait too long to let them confess? Will they fall out of love if I don't turn the game on? My 2nd and 3rd Mii are "ready to risk it all" with each other and they seem to try to confess, but the game won't let them.

I'm worried by the time the game comes out, they'll fall out of crushing. Can that happen?