Playmates is fine by me, why ruin it?

I am in a non-relationship and i like it that way. We enjoy each others company and enjoy a good sex life then return to our respective lives. but recently the guy looks at me in this gooey eyed way and it makes me feel guilty. I am happy to go on the way things are however, I don't want to hurt him by keeping him at arms length but then again i don't want to lose him by bringing it up....what to do?