What ever happened to the bonding that you and your wife have with the daughter. You sound as though this is a done deal and you are just left with dealing with your hurt feelings.
You wonder how this man could afford all that he is affording. Nothing wrong with finding out. You suspect something shady. Ask the questions. Your daughter is not of age yet. Would your wife be countering a custody court order?

You don't have to argue with the daughter. Yes, she is old enough to be making many of her own decisions--but then so is a five year old. Has the research been done with the school she would attend, and is it known if she has her majors and minors, etc. in order and her schooling won't get all screwed up. If your daughter is being serious about herself, you would know it. Your intuition is a great tool--listen to yourself. First things first. Do you agree that her school work is too hard for her?
If there is any validity to what you are imagining--are you and your wife going to kick yourselves because you let this girl walk into WHAT, you don't know. Pull up your boot straps and say NO WAY and we won't talk about this until I have some answers that make sense. Too soon. Too many loose ends. You don't feel good about this for a reason. Listen to yourself. May the Spirit guide you.

We had a similar situation, though the move wasn't as far (but it WAS 2 hours away). My husband's ex decided to move to a fancy house and to take his daughter to begin her senior year at a new school. They lied to the school in order to do this (actually -- you could inquire at the school -- there are rules against moving a child at that stage, so maybe the school would not accept her anyway). It was a similar situation -- mom had no rules, gave her whatever she wanted, moved to a huge house in a gated community,etc. Very difficult to compete -- especially when you try to teach the children values and refuse to compete with that (as we did).

Bottom line, as brass tacks said -- do some investigative work on this guy. If he has all this money and you don't believe it is legit, perhaps you will find out something that will ensure that a court would never allow her to move. Also, sharing info with her may help her realize it would be a bad move (and at 17 it is time for her to have some hefty doses of reality....not sugar coating her father to her).

I totally understand how you feel hamsteve. Betrayed by sd.

You have loved and cared for this child for years and now it is almost like she is giving you a slap in the face, saying I don't care that you have been there all these years for me..... I am going to live with my real dad! Thats it, thats all!

Remember she is 16. And girls at that age have the attitude that they honestly know everything there is to be known it this world!

I don't know that it will make a difference if you show her how wrong it would be to go there - that the school isn't so good, etc. etc. etc., that she will have to make new friends, etc.

She wants to go. She thinks it will be great.

Of course, she is too young to know what is best for her , but what can you do?

It doesn't matter what you tell her - it won't change her mind. She doesn't care if it hurts you. Actually, she probably hasn't even thought of that aspect of the situation. Right now, it's her, her, her, her that counts.

You are not out of her life and you never will be because you aren't giving her the big toys. Believe me. My step children (the two i get along with) do appreciate me in ways I would never have thought sometimes. They are older now so they remember things i did or I showed them, even the most simple little thing; it's so sweat when they remind me of stuff like that. They say I am their mother in their heart! I've always told them they are my children in my heart!

Believe me, SD will be crying for your wisdom soon enough, just like she has since she was four.

She loves you but right now she also thinks she loves her biodad. We'll see.

It is good to detach ourselves with love from the people we love and who hurt us sometimes unintentionally or intentionally.

Bonne journée.

Thank you all for your comments. Please keep them coming!
An update on my situation. Things are getting more confusing to say the least.

SD has moved the date of her departure (to go to FL to live with BioDad) twice now. First the date was after Christmas day, now it is right after New Years so that she can spend New Years with her steady boyfriend. Obviously things are not, and never have been, oppressive to SD at our home. SD has developed her first real steady boyfriend, both 17 yr's old, and they see each other most every day. They have played by the rules and we basically like the young man. Yet, SD is still openly planning to move in with BioDad in FL. Leaving behind not only her friends, her mother and me, and now her first steady boyfriend of 3 months now. We just can't understand why SD is willing to leave so much behind to go live in FL where she will start over, mid-year in 11th grade, have to make new friends, just to get some big ticket toys. I am so disappointed in her decision. I do believe that she will move.

BioDad has told SD that he is going to place her in a church group, force her to be active in his ("born again" style) church, and that he will allow her to live in the "private apartment mother-in-law suite" in his new "country club" style home. SD will atend the local public High School, and BioDad is supposedly promising a "white jeep" and a cell phone with unlimited minutes, new fancy bedroom furniture, a couch in her "apartment", etc. BioDad is also saying that he will "make her successful in school so that she doesn't just have to marry for money" Really! This is all so weird to us. We were active in a church (Methodist) and SD refused to go after she turned 15.

Why in the world is SD willing to walk away from her life with us, and into this situation I describe in FL? And leave her boyfriend behind explaining to us "if it was meant to be, it will last." SD is definitely planning to move on Jan 3rd now, and the plans are all seemingly in motion. Funny thing is, SD is apparently not returning BioDad's phone calls very often. SD is still telling us she is definitely moving. What in the world do you think is going on here? Thanks for your ideas and insight!

Not to get your hopes up, but it sounds to me like SD may be "all talk"...

Now that things are coming down to the wire, the scary realities may be setting in, and she may actually be realizing that being "born again" into a whole other life isn't really what she wants. But she isn't willing to lose face yet by admitting she was wrong. She has verbally defied you and asserted her independence by stating that she will move -- Verbally she has 'taken control of her life' -- but she may not be quite emotionally ready to follow through.

Is there any way you could engineer a face-saving way for her to change her mind? It would have to be a 'no-pressure' thing where she would in no way be seen as 'giving in' to parental pressure -- What about 'The Prom'? or 'Spring Break in Florida'? (Easter at a born again church could be an eye opener.) Any opportunity you can think of that would get her to choose to 'delay' the move -- but not make it look like you're wanting to control her.