@tigerstar186 Not necessarily. Everyone has personas, usually more than one like how you act at work vs hanging out with friends. Now, being forced into a persona does actually cause psychological repercussions, but thats not what happens here. On the contrary, I would argue that this is quite healthy. Instead of repressing her desires to do or say something as "Rin" because its too embarrassing she can simply don another persona and express herself that way.
More than one NTR scenario possible it seems. When they are married, she can act as another girl ntring herself. That is really weird to think of, but... wholesome...?
What does he mean she started acting without him prompting her? This isn't the first time that happened. Not sure why he's acting as if its the first time now...