This is a great asset to the relationship. Unemotional does NOT equal uncaring. Man tends to show his caring more by doing things FOR his partner than sharing feelings WITH his partner. Men usually find their identity through their accomplishments. Women usually find their identity through their relationships.
Men gain their highest sense of self-worth by achieving goals and completing tasks.
Usually their work is their main source of pride and self-esteem. Conversely, women tend to find their highest sense of self-worth by having family members and friends that they can feel close to. Quality connections with others are important to them. Since his partner may spend a lot of time with nearly everybody that is important to her, he can feel ignored. He could easily get the impression that she pays too much attention to others while leaving him out.