I’m sorry you are feeling so unsatisfied in your relationship. It’s difficult for me to offer you an explanation beyond what you yourself guess. You said that he has had exams so it could be he put his school work as his number one priority until the exams are over. You also said his former girlfriend ditched him so it could be that he is scared to invest much in a relationship again. Keeping his distance protects him from heartbreak. You said he’s inexperienced in relationships. In that case, he may not know what you expect or how to be a “boyfriend.” Or it could be that he’s not that into you and he doesn’t know how to break up with a nice person who is just not the right one for him.
Unfortunately, since neither of us is a mind-reader, we’re left guessing. If talking doesn’t work, it could be he doesn’t really know what he thinks. It could be he doesn’t like to feel on the spot. Or it could be that he doesn’t have the emotional language to talk about feelings.
My only suggestion is that you try writing him a letter – not a text but something longer and more heartfelt. Tell him how you feel and ask him for an equally honest and heartfelt answer. A letter often elicits a more thoughtful response because it gives a person time to think about what he might want to say.
If the relationship continues to be unsatisfying, then find a way to kindly part. From what you say, he is not a mean guy but he may not be a match for you. Send him off with the wish that he finds the person he needs. Then make yourself available for someone who is more your type.
I wish you well.