Please Advice Me: I’m 22yrs Old, have dated12 Men, had 7 Abortions and wants to marry a good man

I’m in my early 20s and in love with a 28-year-old man. He has a good job and he is quite nice to me. I always feel that any girl who is not a virgin should not marry him.

We have been together for a year and he has promised marrying me but he doesn’t know my past deeds. I have this innocent and youthful look and he would never know that so far, I’ve dated 12 guys and I’ve had seven abortions.
He has planned our marriage for October and I feel guilty not telling him what I had done. I feel that if I tell him, he could change his mind and break up with me. I don’t think I can get another man like him.
What do I do? Tell him and lose him? Or keep quiet and get married?