Should I tell him? Need guys advice..?

Ok so here's the back story to my question. I started seeing this guy a few months ago. We work together and he's a few years younger than me. I was all about him but he was reluctant. He didn't want a title. When people would ask him he would say that we were just "good friends" Someone had told him that they thought I had another boyfriend and he said (and he told me this not anyone else) that he's not the jealous type and he didn't care if I needed a thing on the side. I wasn't happy about this and told him I wouldn't be in an open relationship. He accepted that. Now I don't want to give the impression that he's neglecting or mistreating me in any way, he is very good to me actually. Things have only gotten better between us, but.. a few days after he said that I went to my friend's house. He was having problems with his girlfriend and wanted to get drunk. We've known each other for a really long time and nothing's ever happened and I honestly didn't want anything to. (cont.)