Was this to harsh?

My (soon to be ex) girlfriend is very clingy, the kind of girl who always needs you by her side and desperately wants to get married. I managed to figure out the code to access my her phone earlier this week (I saw her put it in from over her shoulder), I was curious so when she went to take a shower I grabbed it and tried to unlock it, it worked. I wasn't planning on snooping but I felt curious and I've been cheated on before, so I checked her messages. I found text messages to another guy who I don't know, talking about wanting her to come over again so he can f*ck her all night long, they even exchanged pictures too. I was shocked, and didn't know what to do, but I quickly came up with a revenge strategy and played everything normal. Yesterday, I went and bought a plastic ring so I can pretend to propose to her, when she said yes I suggested we get matching tattoos, it was always an idea she loved but I never liked it. She was literally crying as she wore her plastic ring and got my face permanently tattood onto her body. When it was done, I spat in her face, laughed at her, called her a cheating whore, and walked out, leaving her to pay for it. Today one of her friends tried to make me feel bad because apparently she's broken down and she's a real mess right now, but I couldn't care less, I still think she got what she deserved. If she didn't want to get hurt then she shouldn't have gone around hurting others. Who was in the wrong?
Was this to harsh?
Add Opinion