First of all, I recommend you watch the drama before you watch the movie. The drama is very short (don't let the first episode length of almost an hour fool you, every other episode is only 20 minutes long and there are only 8 episodes in total!) but without watching it I feel like one important message might not come across, and that is that every story has different perspectives. The drama basically only shows Rios side, what she makes out of the info the four women give her. The movie, however, shows Ito's experience. I had some free time so I binge watched the drama and movie in one go and while the Ito of Rios perspective (drama version) felt a bit inconsistent and like the biggest jerk out there, Ito's perspective was a lot more congruent and likable. Like a review before me said, Ito is not a jerk at his core. He avoids getting too involved with other people because he thinks that way he can't get hurt, which makes him act aloof around other people and ends up hurting them. Still, we get to see that even though he puts up a front, he has feelings and those feelings can get hurt. I think Masaki Okada's performance was outstanding and really brought a multi-faceted Ito-kun to life.
The women in this story are not perfect either and their behavior and problems seem very real. Each of them has a totally different view of Ito, showing how subjective we perceive other people and how we might even unconsciously push our ideals onto them. Through their encounter with Ito and also through their "counseling" with Rio, they are able to truly look at themselves, grow, and move forward.
All in all, I enjoyed the drama and the movie together very much. I recommend it as a package to everyone that likes movies about human flaws and growth. The romance tag might be a bit misleading, though. If you expect the typical rom-com sweet kind of romance here you could be disappointed.