Sister who can not decide marriage

I am a new user. I came to know about this site through google search. I’ve been wanting to ask someone who is willing to help me instead of loathing or mocking my dilemma. I would very much appreciate any honest thoughts. Please be prepared for a long narration. 

I’m an unmarried woman who did haram actions with another man. This man was my secret boyfriend for many years. Although our relationship was physical, we did not go all the way because I fear unwanted pregnancy. Please take note that I’m very guilty of what I did and even now I felt so ashamed talking about this problem with people I don’t even know. I can not tell my parents about it or anyone close to me. 

To continue my story, this man promised that he will marry me. I’ve been waiting for years for him to ask my father but he never did. He will always tell me to wait a little bit because he’s not yet capable. After many years, I got a full time job. I became very busy and eventually we rarely meet or talk. Now it’s been half a year since the last time I sent a break up message which he did not respond. I did taubah and pleaded Allah to forgive me for my past sins. I came to realize how st**id and naive I was to commit a grave sin. Now, a new man came into my life. He is very different from my ex. A relative introduced me to him. He is studying the Qur’an and wants to marry me thinking that I wasn’t involved in an illicit relationship. My dilemma, should I wait for my ex or should I marry this pious man without telling him of the truth? I have photos with my ex during our dates and I’m afraid he might revenge once he learns I’m marrying another man.