The terms "old girlfriend/boyfriend" and "ex-girlfriend/boyfriend" are often used interchangeably, but there is a subtle difference in their meanings:
Old Girlfriend/Boyfriend: This term generally refers to someone with whom you were in a romantic relationship in the past but are no longer together. The emphasis here is on the fact that they are from your romantic history and not your current partner. It's a more neutral and less emotionally charged term than "ex."
Ex-Girlfriend/Boyfriend: The term "ex" is short for "ex-partner" or "former partner." It specifically indicates that the person was once your girlfriend or boyfriend, but the relationship has ended, and you are no longer together. The term "ex" implies a more formal end to the relationship and might carry some emotional weight, especially if the breakup was recent or if there are unresolved feelings.
In summary, the primary difference between the two terms lies in their emotional connotations. "Old girlfriend/boyfriend" is a broader and less emotionally charged term that simply indicates a past romantic relationship, while "ex-girlfriend/boyfriend" explicitly suggests that the relationship has ended, and there might be more emotional significance attached to it.