Looking for advice to initiate a crucial conversation?

Simply put - have been dating a guy for 6 months. He has been staying at my house nightly and I'm beginning to feel suffocated. I have been able to talk to him about anything...except this. As I type this I realize that if he loves me and I ask him for space he will be understanding. I also understand that even though I feel by having this converstation he is going to hear either it's "all or nothing"...and in that case does he really love me that much. So what I am asking here...is to somehow have this conversation, not put him on the defense, help him understand that I do not want to live together for a while yet. My goal in the conversation is to ensure him that I indeed love him, see great potential for the relationship, however, I am not ready for a roommate.