Beitrag
von Enceladus »
I think it's fine as both "Gone but forever in my heart." and "Gone, but forever in my heart."
Personally, I think it's a bit better with the comma, but it isn't obligatory.
The use of commas in English isn't as strict as it is in German. A lot of the time (but not always!) it's up to you to decide when to use them.
Sorry that this is in English, my German is still very limited.