Not exactly.

INTJ’s, with their tertiary Fi, feel deeply. What they struggle with is expressing those feelings in a way that other people can understand. While they may recognize that they are having A Feeling, they may have difficulty consciously identifying what exactly that Feeling is, especially in the moment. If they do identify it, they may not be able to translate their internal emotional experience into words and actions.

One way INTJ’s cope with this is by mimicking emotional expressions they have seen in others. They develop a repertoire of socially appropriate scripts as responses or expressions. This could be verbal (saying the right thing) or non-verbal (putting on a the correct facial expression). If a situation becomes more complex and the INTJ runs out of scripts, it may appear, to the outside observer, as if they have emotionally tuned out of the situation, but in fact they just don’t know how to proceed.

To a Feeling type, what I’m describing may sound, as you said, as if these expressions are not “true,” or are somehow inauthentic. But this doesn’t, generally, come from a lack of authentic feeling, but instead from an inability to communicate those feelings in real time.

Not all INTJs do this, and even those that do don’t do it all the time. INTJs may employ scripted responses to navigate small talk or encounters with people they don’t know well, but not use them with the people they are closest to. They’re also less necessary when talking about long-term states (i.e. being in love or missing someone) because the INTJ has time to analyze how they feel and formulate genuine ways of expressing those feelings.

In short, I would not assume that what your boyfriend tells you about his feelings is somehow fake. I would guess that his feelings are probably very genuine, run deeper than you realize, and are very difficult for him to express but he’s figuring out how to do it for you. The way he’s saying it might be pre-scripted (though not necessarily,) but that doesn’t make them inauthentic.