I went on what I would call a "date" recently with a man I just met. He asked me out for coffee, and we went out together and had a nice time. Then, when I saw him again recently, he told me that he had a girlfriend but that he still wanted to "hang out" with me. He also told his girlfriend he had made a new friend who he invited out to lunch. What gives? Should I continue to hang out with this guy? Is he interested in me romantically or does he really want a platonic hip?
It's difficult to know what this guy's intentions are. Whether or not he wants a new friend or a "special friend" probably depends on the status of his relationship with his girlfriend. Are they in a serious, committed relationship or is he (to quote High Fidelity) "maybe, kind of looking around for someone else?" Either way, it sounds like he's probably not great dating material for you at this time.
If you believe that he really wants to be with you, and you'd like to be platonic with him as well, why not tell him that you'd love to hang out again with him AND his girfriend. You could say something like, "I'd love to have lunch next time with you and your girlfriend. After hearing about her, I'd really like to meet her and get to know her, too." If he accepts the invitation,you could be reasonably sure that he's sincere about a platonic hip. If he acts squeamish about it, then chances are he's probably looking for " with extra." In that case, Ask Gothamist advises you to delete his phone number, erase his e-mail address, and find someone to date who isn't heavily involved with somebody else already.