Tbh this shouldn't be that bad of an end. If the character progression is love without being eaten, they're practically there. Stretching it out would be a bad move.
Prediction: Prince is doing this because he thinks the attempted NTR will make Mino rage. Mino won't rage because he mostly views Ruvine as a friend. Ruvine will, however, rage as she has actual feelings for Mino and understands what's going on. She starts a fight and Mino comes to her defense.