Would she regret it and remember me ?

she WILL always remember all the great things you did for her, and eventually she will come to realize she made a huge mistake when she realizes how much you loved her, cause like you said "he likes her" and you loved her. I think it's kinda messed up that she dissed you for someone elseafter the way you treated her, and mark my words, "She will be back" it's up to you to take her back or not when she does though. Good luck! and sorry to hear that :(