The behavior Terell is experiencing is his own insecurities and doubts and projecting them on to Kim. Most people would refer to this certain behavior as "overprotective," which it can be. However, most of the time, it's much more than that. As I stated earlier, Terell is projecting negatively to Kim, and if it doesn't stop or be reduced at the very least, it can literally open a vulnerable spot for Kim to be manipulated and controlled by Terell. This is a sign of mental abuse. From a psychological point of view, I do not think it is healthy for Kim or Terell to get married to one another. Imagine if they were to marry; Kim will have a harder time living her life independently because now she's legally bound to him and even if she wanted to divorce him, it would be very costly to do so. It would also make things more complicated if they ever end up having children with child custody and other legal issues with that.