How do you make your boyfriend feel mentally connected to you? Is it something that is just there or can it be built? People say that mental connections make people want to stay in relationships and it is more important than just a sexual connection.
You can't force communication. Both people can't be afraid to be vulnerable with each other which is a rare thing. When there isn't a strong connection and communication the relationship slowly withers and dies in my experience. Sometimes two people just aren't right for each other either.
It has to be built through conversation and experiences. The more you get to know about each other the more you will pick up on how each of you is feeling and why. This will start to allow you to kind of be in, each others heads a little and connect better.