I feel like the slow build up from first meeting him to becoming incredibly possessive was done well, and I think the resolution was pretty realistic. Outside the bar setting they talked, set boundaries, and she took a step back and realized she was going too far. She now also knows where Masata stand with her beyond just being a customer. Masata basically pulled her head out of the proverbial sludge she was drowning in and helped her snap out of her crazed place her mind was in.
That being said, we will without a doubt see that side again once she starts interacting with the other girls chasing Masata.