Ring Etiquette?

As much as it has the significance for you, in total honesty, I wouldn't feel happy being given a ring originally intended for someone else. It doesn't really show though for your fiancée, as you didn't pick it for her and she may well discover the truth of its origins which could be problematic for you. Not wanting to upset you but you really should choose something for her not for you

Unless you asked her and she was happy with this, I would say no. Many women would feel uncomfortable being proposed to with a ring that was bought for proposing to someone else. Also, have you considered her tastes? I'd be surprised if both your previous girlfriend and your current one had exactly the same taste, so it sounds as if you may be thinking of an engagement ring in terms of what would be meaningful to you instead of what your girlfriend would find meaningful.

Agree with the above comments. As the ring is meaningful to you, could you consider having the stone reset in a setting she would like / reusing certain elements but generally remaking the ring so it’s for her rather than how it was for someone else?

I feel like it’s probably not the best idea 😬

I appreciate everyone's input. You've solidified what I kind of felt anyways, although I didn't even think about reusing the stone(s).

Have a great day!

I’d definitely suggest what others have. Change the setting on the ring perhaps and wishing you both the best of luck