What is wrong with a person who cannot give a compliment ?

My boyfriend cannot give a compliment, although he loves to get them. When I asked why he can't do this, he replies that he has been told this before. But still, he doesn't give any compliments. I can spend an hour dressing up to go out or spend a day in the kitchen preparing a meal and he neveer says a nice thing, etc. After a while, it almost seems undermining. What is wrong with him? I thought when you love somebody you want to tell them how much you admire and appreciate them. It comes naturally. So, I don't understand him. Does anybody have any thoughts on this? Is it some kind of pive-aggressive behaviour?".