You probably can’t make yourself a whole lot less sensitive a person. In fact, there are to being able to easily connect emotionally . . . but that’s not what this question is about.
To keep yourself from emotional attachment (to everyone), raise these two things: boundaries and standards.
Let yourself be an onion, a castle, a lobster…
In other words, use protective layers to guard and keep fixed circles of connection that span from shallow and distant to close and intimate.
Don’t let anyone cross from one circle to the next unless they first earn appropriate trust.
But how can you choose to do that? How can you maintain those protective layers and circles? How can you keep your heart from desperately flinging itself across to grip and pull everyone in?
The answer: Learn to raise your standards.
Here is a list of treasures: your heart, your time, your , your future, your dreams (both and in life)…
Relationships are two-way streets, and what you mean to someone doesn’t necessarily have to be the same as what they mean to you; so I’m not talking about refusing to acknowledge or interact with anyone that doesn’t serve or benefit those treasures listed above.
But raising your standards means seeing your treasures as important enough to protect—to not let someone cross your circles who won’t support and contribute to those valuable aspects of who you are.