"Friends"

Cass
So today my bf asked if he could have a girl that a friend. Which is weird in mY book because we either share friends or have same gender friends. He said he met her at a store (where she works )and that they talk and blah blah but he said I can't go where he goes which is where she works because she doesn't know that he had a girl friend. I see something wrong with this ? Do you ? what do I do ? He says he love my and whatever, we have 5 yrs but why doesn't he want me to go. What's wrong with this picture ???