TIFU my engagement

Throwaway account.

I (28m) was supposed to get engaged to my gf (25) yesterday. I purchased the ring a few weeks ago. Prepared my speech. I even rehearsed my proposal with the assistance of my friend (25f), whose job was to be my stand-in gf. No one knew about my plan to pop the question other than my friend. The two of us rehearsed more than once on more than one occasion because I was OCD about what I wanted to communicate to my gf when I proposed. My friend behaved nothing like my gf, but she low key made an effort and I appreciated it. Towards the end of our last rehearsal, my friend unexpectedly kissed me when I put the ring on her finger. I pulled away and expected her to justify the kiss with a joke about committing to her character or something. Instead of joking, my friend said she loved me.

I had no idea how to respond. My friend continued talking and said the time we spent rehearsing convinced her that the feelings she had for me were real. I said I didn't feel the same. My friend became emotional and decided to leave. I didn't stop her, but I should have, because she still had my ring on her finger. I called and sent messages as soon as I realized the ring was gone. My friend ghosted me. She disappeared for days. Her roommate was clueless about her whereabouts. All her friends were equally clueless. Apparently. My gf sensed that something was wrong and asked me to explain what was going on. I came clean. Explained the whole situation.

My gf got upset. It made no sense to her that I put her ring on my friend's finger in the first place. She said her answer would've been yes if I asked her to be my wife. But there was a but. I played marry me with my friend, who I apparently had no romantic feelings for, instead of with the person I supposedly loved more than anyone. I struggled to convince my gf that the rehearsal was innocent from my side. She blamed me for creating an intimate environment that encouraged my friend to be intimate back. I got the "I told you so" speech dipped in "now you know why I never trusted your so called friendship with a girl who always smelled like sex."

My friend resurfaced less than a week later. She returned my ring with an emotional apology. I apologized for hurting her feelings and suggested that the two of us keep our distance for the time being. She agreed. It was not enough for my gf. She wanted me to end the friendship forever. I was hesitant to go that far. I knew my friend since childhood. My gf put our relationship on pause until I made up my mind. Like I stated at the beginning of my post, my plan was to propose yesterday. However, I've been unable to decide what to do, and now my friendship and my relationship are in limbo.

TL;DR I rehearsed my proposal with my female friend. The rehearsal prompted my friend to reveal that she was in love with me. I did not share the same feelings. My friend disappeared with a broken heart and with my ring. I informed my gf. It made her upset. My friend eventually returned the ring, but the damage was done. Now my friendship and relationship are both question marks.