Why does everyone think being friends with a married man is playing with fire?

Why is he calling you from a pay phone? Is he hiding you from his wife? If he is, then yes you are playing with fire. You already admitted that you like him - that's not good because you are putting yourself in a vunerable position. I would cut ties with this guy; sounds like it will only end up in heartache in the long run. Find someone else to date that isn't married...he can't be much of a best friend if his wife doesn't even know about you...