Because A - He will never be jealous of what you do and the career choices you make, because he's been there.
And, B - He'll actually help and encourage you to make the move you've been dreading. If your man is older than you, you know what I'm talking about.
According to psychology, the attraction towards older men might have to do with the relationship you shared with your father.
Tell her what kind of man she should look for when she's older and tell her love is not like in the movies.
Also, tell her how beautiful and smart she is everyday because girls need to hear that, especially from their dad or some sort of male figure. Whatever you do, support her decisions and don't criticize. Only support, this doesn't mean just for boys, try to support her in other interests that you think are appropriate in hopes that she will get more focused on music lessons or sports than on the guy.
You could either be looking to find the same kind of love, protection and care, or you could be compensating for the love you never received.
Well, no matter what the psychological, Freudian theory might be, we have our very own reasons.