Told my boyfriend I gave my number out-unappreciated?

My boyfriend has always taken my love for granted even after all the hard work and dedication I put into our love. I was faithful and true to him, and all he did was out be down and made me feel less than what I was. He always doubted my love even after I accepted him and all of his insecurities. I was tired of crying and him hurting me so to get back at him I gave my number to another guy and told him abut it. My boyfriend found out and was crying and spilled his love for me. And told me he wants to marry me and he is sorry. I dont know what to do. I love and want to marry him to, but he has to change and it wont work. Am I wrong for giving the guy my number? The guy knows i have a boyfriend. But my boyfriend says he cant trust me anymore. But why should I trust him when every time i gave him my heart he broke it.