If she's wary of traffic, you can't push her to be comfortable on the road. It's something that you learn on your own, imo. It takes time, years, to learn the ropes of riding aggressively/defensively to know what to do to keep yourself safe (hah, as safe as you can be) in a chaotic environment.
I can't think of anything more likely to put strain on a new relationship than her feeling that you are endangering her life with a hobby. Enjoy your time together without planning out your future just yet. Go car camping and see how that goes. Go bike riding on groomed dirt roads in scenic places like around a lake. Take it from there. If you become a very fit couple bike packing might be a better idea.