Do you mean sexual passion? Or that excitement/passion you felt when you were first going out?
You have to take action to get either back. That initial "new relationship" rush is hard to get back at that same level, but you can try. Do new things together. What new things do you want to try? Go to the jungle? Rappel into a cenote? Zipline at the top of the jungle trees? White water rafting? Try a new hobby?
As far as passion in the bedroom, try fetlife.com. It's a social website for kinky stuff. Plenty of ideas there. The basic membership is free and you get a lot for it. And remember: safety first. Don't try something dangerous unless you read up about it.
I have to ask: is your gf open-minded enough to try new things? Costumes maybe? Let's be honest. Some girls are just plain boring vanilla.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
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