My boyfriend wants to be with me "All the time"...?

I have this issue with my boyfriend. He wants to be with me all the time. We even work in the same place so that makes it so tough for me that i feel suffocated most of the times. We are together at work almost 9 hrs a day and then he insists that we go gym together post that, making that almost 10 to 12 hrs a day together(including driving around). And he does not spare weekends either. He brings up sumthing or the other and insists on meeting during weekends too. He includes me in his work travel too even if it does not makes sense for me to be there. Apart from that he calls me about 5 times a day!! I understand he loves me a lot and i love him too, but this has been too much of him and am not able to handle it. I just tried telling him in a nice way without wanting to hurt his feelings, but I don think he's taken it too well. Now he is behaving too weird and purposely distant. How do i make him understand that I love him a lot but still i need my space, and that I will not run away if he stops clinging on to me the way he does now. Please help.