What is going on in his head?

ive been seeing this guy for over a year,nothing offical yet. he said he doesnt want a relationship and i know hes not fooling around on me. after a year,im almost positive of it. today i asked him, "hypothetically..if i was to have another man i was seeing taking me out,sleeping in my bed,kissing me and making love to me in rotation to you..what would you do?" he responded with it would change things with us because its not cool to be with two people at the same time. he also stated he cant get mad at me for it if what i want is a serious relationship..he doesnt want to hold me back from that. this,to me is all very confusing. he says were not commited but if i test the waters with other men and then things will change (even worse than now) which i could only assume he'd sever ties with me. its like commitment with nocommitment. its like strings attached with no strings attached..but..with the strings..attached. can anyone make any sense out of this? its like hes trying to convince himself of something. im not concerned about the status of the relationship as much as i am curious about what kind of "logic" is behind all this contradiction. if i see other people its okay but it would change things? at a smaller point whats the best way to help him come to his senses. ive decided i should cut contact down.