“Love you guys,

Jessica”

However, being a woman, I can understand why your GF would initially be upset. Woman as a rule are much more literal and we can’t help but look for the underlying meaning, even if there is none. If you look at it in a technical sense, she may be thinking “all your love” is going to other people and not to her. In order to compromise, maybe you can still express your caring nature while keeping your GF’s comfort level in check by signing off in a little different matter. Such as:

“In friendship,

John.”

Everyone else gets, ” Best regards”, “Kind regards”, or simply “Best”.

For business letters “Sincerely” does the job.

If I were your girlfriend/fiancee, I’d be annoyed with your use of ” All my love” to everyone too.

Would you say “all my love” to a male friend?