Well, I say take the relationship down. Sorry, folks, the 20 something girl doesn't love her man anymore. She wants to leave him. Won't have sex with him. It's now a relationship in name only.
she is good for me because she has no self esteem and wants to give up control
Then take complete control over this woman. She wants it and needs it. But, if you were truly an educated, smart man, you wouldn't send a woman who already has low self esteem issues and make her feel even lower.
ikes to be abused sexually and physically.
Ehhh.....I'm very against this. Abuse is a terrible thing, so, try to be the well-educated older man that you are and DON'T abuse her. You should be ashamed of yourself. Using her for sex, turning her into a slut, I guess is OK, abuse (slapping, hitting, etc) is just twisted. And, the first time things go south, she can have domestic violence or assault charges brought against you. Be smart.
Incidentally, I will be curious to see if, once the cuck relationship is over (that is, she is away from her hubby for good) whether your feelings toward her change. Right now, she is a play toy. When it's just you and her, it will be something different. And, the above posters are right, once she leaves her husband, the cuckold relationship (and probably some or most of your fun) ends. Then it's just you and her.