How do you say , "goodbye forever" to someone? In sort of TV playful dramatic tone?
Example: You're boyfriend/girlfriend is leaving the country, or someone you won't see ever again.
Is it this? 영원히 안녕
I guess you're asking something like Adieu or Adios. I haven't heard of saying 영원히 안녕 though. Alternatively people says:
There may be some others too.
If you really mean to say 'goodbye forever', you may say:
"영원희 안녕" could be a literal translation and I don't think it's weird to say. Probably it could be very attractive and/or famous to say depends on TV show's context and who speaks when/whom under certain situation. In Korean language, "결별" could imply something like "forever goodbye"... but it would sound weird someone say 결별 in the TV show. It's more written language style I guess?