This seems very, very, very predatory to me.
"Showing her how it's done" shouldn't entail trying to manipulate her into living with you and your husband or having sex while recovering from a bad relationship. Showing her how it's done SHOULD be helping her find a neutral, safe, supportive environment where she can grow as a person and figure out what SHE wants, not what YOU think she "needs." Not a place where she is going to have some guy think he's going to make everything better by fucking her.
I'll be 23 in a few weeks. If someone suggested to me that I should move in with him and his pregnant wife (or wife who has just given birth) so he/they could show me what a healthy, normal relationship is like, but of course I would have to have sex with him to really learn, I'd run the opposite direction.