she had sex with someone else just days after we broke up

oh man today we texted and called. she already had sex with someone new just a few days after i broke up.she said shes gonna love me forever and said she thinks shes over our relationship already. ( how can you be over it just after a few days )well at least we are on good terms now. and i apologized for the way i broke up and it meant a lot to her.we wont have contact and she said she also doesn’t want to be with me anymore. previously she would always try and get me back.im kinda happy we didnt fight more and made peace. but yea sex so fast.. i dont even feel ready to have sex with someone new so fast. i hope i‘ll be goodand i don‘t believe shes over us so fast