MY FRIEND IS CHEATING ON HIS FIANCÉ AND I DON’T KNOW IF I SHOULD TELL HER

My good friend and his fiancé have been together for a while now, they have been engaged for two years. I’ve liked this lady for a long time now and I know my friend doesn’t deserve her, she’s too good for him. He’s cheated on her multiple times with multiple women, she doesn’t even know about it. He tells me he’s with her because she will make a good wife, she has a good job, good morals and goes to church. She’s focused and knows what she wants. I asked him why he cheats on her and he said it’s because she’s not exciting, she’s not fun, she’ll make a good wife because he’ll be able to live two lives. He says he will have a good wife home and he will have an exciting life outside the marriage. I think it’s selfish.
He controls her, and it’s amazing how much she listens to him, she treats him like a king, she does whatever he asks. I remember the time he cheated on her and she was really shaken by it she surprisingly forgave him after two days. It really hurts me to see a good woman like her with a bad boyfriend, my friend is a good friend but he’s not a good partner. The things he’s doing now are only going to get worse after he married her. I’m really concerned, I have tried to advise him to stop playing now that he wants to marry her but he says I’m just jealous. I’m not plotting against him and I don’t want to take his woman but she deserves way better.
She thinks he has changed, from the conversation I had with her, she thinks he has changed but he hasn’t, he’s not even planning on changing. I don’t know if I should tell her.