can a stepfather who adopted his now ex wife's dauther reverse the adoption

Nope.

Unless someone else that is qualified and legally allowed steps up and takes over your responsibility, you are this child's legal, emotional and financial guardian... you are even subject to child support and visitation rulings.

Children are not appliances that can be returned when you no longer want them.

Jeff is absolutely right! Once you adopt, only another potential adopter can get you out of it. Please expect to be hit for child support. I certainly hope that this child you felt close enough to adopt, still sees you even though you two divorced. So you know, you have legal rights to see her, if mom is not letting you!

Why would you do that to a child that has already lost one father?

Because some fathers think that the adopted child is no longer their responsibility when they divorce the mom.

Somehow, they didn't get the memo that stated that marriage may be temporary but fatherhood is forever.

That and their balls start to shrink up into their arse's when the words "child support" are heard.

I guess the poster didn't like what he was reading since he has not returned, that poor child, I hope he decides to get his head out of his ars and continue to be there for the child!!